SoundAdvisor Model 831C Sound Level Meter Reference Manual€¦ · • Measures sound: stop, pause,...

SoundAdvisor Model 831C i-1

Larson Davis

SoundAdvisorModel 831C

Sound Level MeterReference Manual

SoundAdvisor Model 831C i-2

CopyrightCopyright 2019, by PCB Piezotronics, Inc. This manual is copyrighted, with all rights reserved. The manual may not be copiedin whole or in part for any use without prior written consent of PCB Piezotronics, Inc.

DisclaimerThe following paragraph does not apply in any state or country where such statements are not agreeable with local law:

Even though PCB Piezotronics, Inc. has reviewed its documentation, PCB Piezotronics Inc. makes no warranty or representa-tion, either expressed or implied, with respect to this instrument and documentation, its quality, performance, merchantabil-ity, or fitness for a particular purpose. This documentation is subject to change without notice, and should not be construed asa commitment or representation by PCB Piezotronics, Inc.

This publication may contain inaccuracies or typographical errors. PCB Piezotronics, Inc. will periodically update the materialfor inclusion in new editions. Changes and improvements to the information described in this manual may be made at anytime.

SafetyIf the equipment is used in a manner not specified by Larson Davis, the protection provided by the equipment may beimpaired.

RecyclingPCB Piezotronics, Inc. is an environmentally friendly organization and encourages our customers to be environmentally con-scious. When this product reaches its end of life, please recycle the product through a local recycling center or return the prod-uct to:PCB Piezotronics, Inc.Attn: Recycling Coordinator

1681 West 820 NorthProvo, Utah, USA 84601-1341where it will be accepted for disposal

WarrantyFor warranty information, refer to our Terms and Conditions of Sale on our website, www.larsondavis.com/TermsConditions.aspx.

i.1 Contact Larson DavisWebsitewww.larsondavis.com

Worldwide Corporate HeadquartersLarson Davis - a PCB Piezotronics division3425 Walden AvenueDepew, NY 14043-2495 USAToll-free (in the US): 888-258-3222Phone: 716-926-8243USA fax: 716-926-8215E-mail: [email protected]

http://www.larsondavis.com

http://www.larsondavis.com/

http://www.larsondavis.com

http://www.larsondavis.com/

I831C.01 Rev M - Firmware Version 4.0.5

Table of ContentsModule 1 Model 831C Features 1-1

1.1 Basic Operations1.2 Applications1.3 Hardware Features1.4 Performance Features1.5 Standard 831C Package Contents1.6 Options and Accessories

Module 2 Instrument Overview 2-12.1 Instrument Hardware Overview2.2 Using the Keypad2.3 Display Elements Overview

Module 3 Getting Started 3-13.1 Unpacking & Inspecting3.2 Connecting the Microphone & Preamplifier3.3 Connecting the Preamplifier to Meter3.4 Disconnecting the Preamplifier3.5 Powering the 831C SLM3.6 Powering On or Off3.7 Operating the 831C Remotely3.8 Long Term Storage of 831C

Module 4 Using the Data Display 4-14.1 Understanding the Live Tab4.2 Understanding the Overall Tab4.3 Understanding the Session Log Tab4.4 Adjusting the Graph Scale4.5 Enabling or Disabling Display Tabs

Module 5 Calibrating Your SoundAdvisor 831C 5-15.1 Understanding the Calibration Process5.2 Reviewing the Calibration Settings5.3 Choosing a Calibrator5.4 Calibrating Your SoundAdvisor 831C

Module 6 Creating a Measurement Setup 6-16.1 831C Setup Manager Overview6.2 Creating a Custom Setup File6.3 Troubleshooting a Measurement Setup File

Module 7 Making a Measurement 7-17.1 Before You Start7.2 Performing the Measurement7.3 Storing the Measurement

Module 8 Managing Measurement Data Files 8-18.1 Setting Data File Storage Preferences8.2 Using the Data File Manager8.3 Saving, Moving, or Copying Data Files

Module 9 System Properties 9-19.1 Setting Instrument Identification9.2 Updating the Meter Time

SoundAdvisor Model 831C ii-2

9.3 Using NTP to Sync the Meter Clock9.4 Editing Power Settings9.5 Setting Meter Preferences9.6 Setting Localization Options9.7 Setting Options On the Displays Tab9.8 Enabling or Disabling Options9.9 Setting Network Preferences9.10 Setting Up Alert Notifications9.11 Setting System Alert Notification Details9.12 Setting Up Cloud Storage for Data Files9.13 Utilizing the Logic In, Logic Out Feature9.14 Setting Reference Spectra9.15 Generating an App Password

Module 10 System Information 10-1

Module 11 Using the Meter Lock 11-111.1 Locking the Meter11.2 Choosing a Lock Mode11.3 Allowing Calibration When Locked11.4 Constraints11.5 Unlocking the Meter

Module 12 System Utilities 12-112.1 Troubleshooting Bad Flash Block Error

Module 13 831C Network and Connections 13-113.1 Connecting to an Ethernet Port13.2 Setting Up the Meter’s Network ID13.3 Setting a Static IP Address13.4 Using WiFi On Your 831C SoundAdvisor

Module 14 Upgrading Firmware & Options 14-114.1 Updating the G4 LD Utility14.2 Upgrading 831C Firmware by Using G4 LD Utility14.3 Upgrading Options14.4 Enabling or Disabling Optional Firmware

Module 15 Using Measurement History 15-115.1 Setting Up a Measurement With Measurement History15.2 Viewing Measurement History Data Files

Module 16 Using Time History 16-116.1 Setting up a Measurement With Time History16.2 Making a Time History Measurement With Sound Markers16.3 Viewing Time History Data

Module 17 Using Event History 17-117.1 Setting Up the Event History Measurement17.2 Storing Event Data17.3 Viewing Event History Data on the Event History Tab17.4 Understanding Triggering Methods

Module 18 Using 831C Sound Recording 18-118.1 Setting Up Markers for Sound Recording18.2 Making a Manual Sound Recording Using Mark Sound Type18.3 Making an Automated Event Sound Recording

SoundAdvisor Model 831C ii-3

18.4 Enabling Measurement History Sound Recording18.5 Understanding Recording Settings and Sound Quality18.6 Sound Recording Playback

Appendix A Technical Specifications A-1A.1 Instrument PlatformA.2 Base SoftwareA.3 Octave Band Analysis Software – Option 831C-OB3A.4 Event Logging Software – Option 831C-ELAA.5 Time History Software – Option 831C-LOGA.6 PTB Approved FirmwareA.7 Frequency ResponseA.8 Declaration of Conformity

Appendix B Measuring Sound Using IEC 61672-1 B-1B.1 OverviewB.2 Section 9.3

Appendix C Glossary C-1C.1 OverviewC.2 Glossary of Terms

SoundAdvisor Model 831C Basic Operations 1-1

Module 1 Model 831C FeaturesThe SoundAdvisor Model 831C SLM is a Class 1 acoustic monitoringinstrument with a full-color touchscreen that measures noisefrequency, sound pressure level, and community and environmentalsound. The “C” in 831C refers to the full-color screen.

G4 LD Utility software (G4) connects your meter to your PC via USB,Bluetooth, WiFi, or TCP/IP. With G4 you can calibrate the meter, createsetup files, download measurements, and analyze the results.

1.1 Basic Operations .................................................................................................................1-1

1.2 Applications .........................................................................................................................1-2

1.3 Hardware Features ..............................................................................................................1-2

1.4 Performance Features .........................................................................................................1-2

1.5 Standard 831C Package Contents ......................................................................................1-3

1.6 Options and Accessories ..................................................................................................... 1-31.6.1 Firmware Options .................................................................................................1-41.6.2 Hardware Options .................................................................................................1-4

1.1 Basic OperationsThe 831C performs the following operations:

TRY THIS Explore the interface, press buttons, change settings, and test the operations.

• Measures sound: stop, pause, and resume measurement

• Display broadband and spectral sound values on a full-colordisplay screen

• View live and stored data while a measurement is in process

• Log simultaneously to time, statistical measurement and eventhistories

• Use markers to annotate portions of time histories, includingvoice annotation

• Automatically back up data to prevent data loss on powerfailure

• Calibrate using a Precision Acoustic Calibrator, and storecalibration history

• Time stamping for Lmax, Lmin, Lpeak-(max) single event metrics.

• Sync clock with PC, attached GPS, or Network Time Protocol(NTP)

• Create multiple Setup configurations using the Setup Manager

SoundAdvisor Model 831C Applications 1-2

1.2 ApplicationsThe 831C monitors:

• City noise

• Construction noise

• Airport noise

• Nuisance noise

• Noise ordinance compliance

• Wind farm noise

1.3 Hardware FeaturesThe 831C is a precision-integrating sound level meter with thefollowing hardware features:

TAKE NOTE Up to 32GB USB memory can be purchased from Larson Davis as an option.

• 2 GB internal industrial grade data memory

• 240 x 320 full-color graphic LCD display with touchscreen userinterface

• Quiet Touch elastomeric keypad

• Meter uses NiMH, photo-lithium, lithium-Ion, and alkaline cells;4-AA batteries provide upwards of 8 hours operating time

• AC/DC output jack with full dynamic range option

• Compatible with 61 m (200 ft.) microphone extension cable (fullscale to 20 kHz)

• Dust-resistant, durable plastic case with lanyard (tripod mountis also available)

• USB 2.0 high-speed host connector for mass storage, weathersensors, USB headset, and WiFi communication devices

• USB 2.0 high-speed peripheral connector for control and datadownload by a PC

• I/O connector for power, weather transducers, logic input/output, and preamplifier communications

1.4 Performance Features• Large dynamic range > 120 dBA

• RMS Detectors: Slow, Fast & Impulse

• RMS Frequency Weighting: A, C & Z

• Peak Frequency Weighting: A, C & Z

• Any LevelTM Simultaneous measurement and display of Max andMin sound pressure levels (Slow, Fast and Impulse detectors),plus Leq and Peak levels, all with A, C and Z frequency weighting

SoundAdvisor Model 831C Standard 831C Package Contents 1-3

• Weather Measurements (Wind Speed and Direction,Temperature, and Humidity with SEN03x)

• Multiple language support: English, French, Italian, German,Spanish, and Chinese

• Field-upgradeable firmware

1.5 Standard 831C Package ContentsThe 831C is available as part of a specialized system, or in a standardconfiguration. The following accessories come with the standardconfiguration:

1.6 Options and AccessoriesIn this section:

• 1.6.1 Firmware Options

• 1.6.2 Hardware Options

Accessory Type Available Items

Microphones (377B02) ½-inch free-field prepolarized microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

(377C20) ½-inch random incidence prepolarized microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

Note: You can use other microphones with the 831C. For more information, see 1.6.2 Hardware Options for more information.

Microphone Preamplifiers

PRM831 PRM2103

Accessory Kit(831-ACC) includes

these items:

(831-CCS) Hard Shell Case

(PSA029) Universal AC USB Power Adapter

(CBL138) USB to mini-B cable, 1.8 m

(WS001) 3 ½-inch windscreen

4 Rechargeable AA NiMH batteries

Desktop Software The G4 LD Utility software (G4) comes on the included LD USB drive. The latest version of G4 is always available for download from

www.LarsonDavis.com/G4.

Lanyard

SoundAdvisor Model 831C Options and Accessories 1-4

1.6.1 Firmware OptionsLEARN MORE To purchase these options, see “Contact Larson Davis” on page ii-2.

The following upgrades/options are available to purchase from LarsonDavis.

831C-LOGTime History data logging with periods from 2.5 ms to 24 hours.

831C-OB3Real-time 1/1 & 1/3 Octave Frequency Analysis.

831C-ELAMeasurement History for the manual or timed storage of statisticaldata, and exceedance-based Logging Analysis with Events.

831C-SRMake event based and manual sound recordings in WAV or OGG formatthat can be sent via email or SMS and stored in the measurement data.

831C-MSRMeasurement History for the manual or timed storage of statisticaldata with all sound recording capabilities.

831C-SWMake direct USB communication with Sierra Wireless RV50X cellulargateway.

831C-AUDUsing the AudCal software from Larson Davis in conjunction with yourSoundAdvisor 831C enables you to test the calibration of audiometersand sound booths.

1.6.2 Hardware Options

The following table contains only a few examples of the hardwareaccessories available for your 831C. Additional components include,but are not limited to, microphones, preamplifiers, software, powersupplies, tripods, calibrators, sensors, protective cases, adapters, andcables. For a complete listing of standard and system accessories, seehttp://www.larsondavis.com/products/soundlevelmeters/soundadvisor/soundadvisorordering.


Accessory Type Available Options

Microphone Options

Note: These mics are available directly from Larson Davis. You can also use other microphones with the 831C.

(377A15) 1-inch, prepolarized pressure condenser microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

(377B01) ¼-inch free-field prepolarized microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

(377B10) ¼-inch free-field prepolarized microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

(377C01) ¼-inch free-field prepolarized microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

(377C13)½-inch, prepolarized, pressure condenser microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

(377C10) ¼-inch free-field prepolarized microphone, 50 mV/Pa, providing performance conforming to Class 1 sound level meter standards

Microphone Preamplifier Options

(426E01) 1/2-inch ICP Low Noise microphone preamplifier (requires adapter (ADP074)

(PRM2103) Outdoor microphone preamplifier

Environmental Protection

EPS Environmental ShellProtects microphone and preamplifier from rain and wind with mounting options for pipes, poles, and most tripods

EPS030-831Weather-proof enclosure for remote noise monitoring; includes battery

NMS/EPS044Solar-powered noise monitoring system for outdoor, long-term, and unattended sound monitoring

NMS/EPS045Permanently-installed, solar-powered noise monitoring system for outdoor, long-term, and unattended sound monitoring

Weather Data Acquisition

SEN031: combined weather sensor, wind speed and direction (with no moving parts), temperature, humidity, pressure, and rainfall (requires CBL170 and DVX008A)

SEN032: Ultrasonic Anemometer: wind speed and direction onlysensor (requires CBL170 and DVX008A).

CommunicationDVX012, 013, 014, 015, 008A 831-INT-ET with integrated

Ethernet capability

GPS GPS001 GPS Receiver, USB Magnetic Mount


Equivalent Electrical Impedance Adapter Options

Choose one of the following adapters in place of the microphone when making very highimpedance measurements. The adapter acts as a series capacitor with the same capacitance asthe microphone it replaces. If you’re making a square wave pulse measurement, include a 100kHz, low pass, T filter with the adapter.

(ADP002) 6.8pF BNC Input Adapter for ¼-inch, 7pF microphone equivalent

(ADP090) 12pF, BNC InputAdapter for ½-inch, 12pFmicrophone equivalent

(ADP092) BNC In-Line, Low Pass Filter, 75kHz

Cables: Extension and Interface Cables

Microphone Extension Cable: EXCXXX (shielded), where XXX is the length in feet (XXX = 010, 020, 050,

100 and 200 available)

CBL138 USB Cable CBL139 AC/DC Output Cable

Accessory Type Available Options

SoundAdvisor Model 831C 2-1

Module 2 Instrument OverviewThe SoundAdvisor Model 831C accomplishes all tasks related tosound monitoring. The 831C is a reliable and diversely competentmeter. With the 831C, you can:

• Measure all area sound

• Stream and record audio continuously or for events usingsample rates up to 51.2 ksps in compressed or uncompressedformat

• Communicate with via USB, Ethernet, cellular, or WiFi

• Operate completely from the device itself, or remotely using G4LD Utility software

• Easily expand memory using USB memory

• Automatically synchronize the clock with Network TimeProtocol (NTP) or GPS for optimal accuracy

• Select desired color theme on the full-color graphic LCD displaywith touchscreen user interface

This module describes the hardware and visual components that makeup the 831C.

In this module:2.1 Instrument Hardware Overview .........................................................................................2-2

2.2 Using the Keypad ................................................................................................................2-32.2.1 Navigating and Selecting ......................................................................................2-42.2.2 Basic Run Functions ..............................................................................................2-42.2.3 Entering Text .........................................................................................................2-4

2.3 Display Elements Overview .................................................................................................2-52.3.1 Changing Display Color Themes .......................................................................... 2-52.3.2 Using Tabs and Pages ...........................................................................................2-52.3.3 About Status Bar Icons and Indicators ................................................................2-62.3.4 Main Menu Overview .............................................................................................2-92.3.5 Tools Menu Overview ..........................................................................................2-102.3.6 Power Control Menu Overview ...........................................................................2-11

SoundAdvisor Model 831C Instrument Hardware Overview 2-2

2.1 Instrument Hardware O er iewFIGURE 2-1 831C Instrument Overview (front)

Standard 1/2” free field or random incidence microphone

Release button to disconnect the preamp from the meter

240 x 320 full-color graphic LCD display with touchscreen user interface (shown with Dark color theme)

Display navigation softkeys

Multicolor back-lit keypad

Tools button leads to system set-up information

On/Off button is also a one-touch power control access

Reset/Clear Measurement

USB Auxiliary port, AC/DC output jack, and I/O connectors

PRM831 Preamplifier

SoundAdvisor Model 831C Using the eypad 2-3

FIGURE 2-2 Instrument Hardware

2.2 Using the KeypadIn this section:

• 2.2.1 Navigating and Selecting• 2.2.2 Basic Run Functions• 2.2.3 Entering Text

The 831C has 13 buttons that are used to start, stop, or pause ameasurement navigate within the display, and power the meter off.

CAUTION DO NOT use the hardware power switch to turn the 831C ON or OFF. The purpose of this switch is to disconnect the batteries for long-term storage (1 to 2 weeks). See 3.8 Long Term Storage of 831C.

CAUTION DO NOT use the AC/DC port as a headphone jack.

1. AU connector intended for use with USB mass storage, cellular modem, GPS, headphones, speakers, and future devices.

2. Hardware Power Switch when set to “ 0 ” com-pletely powers down the 831C for storage. Set to “ ” for instrument operation.

3. USB Interface 2.0 peripheral full-speed port used for communication, full control, and download-ing of data to PC. The PSA029 external power supply may be connected here. The maximum USB cable length is 1m and the cable is part number CBL138.

4. AC/DC 2.5 mm Output jack for analog AC/DC out-put signals.

5. The I/O Connector for peripherals and external power is typically used for external devices.

Navigation buttonsUp, Down, Right, Left

Reset a measurement

Power

Access the menus.

Stop or Store a measurementRun or Pause a measurement

Select or Enter

Softkeys: LEFT, RIGHT Navigate display tabs CENTER Close or exit a menu.

SoundAdvisor Model 831C Using the Keypad 2-4

2.2.1 Navigating and Selecting

To navigate the display on the meter, you can press directly on thetouchscreen using the tip of your finger, or use the navigation buttonsas shown in Table 2.1.

2.2.2 Basic Run Functions

The basic run measurement functions can be executed using thebuttons as shown in Table 2.2:

2.2.3 Entering Text

Table 2.1 Buttons for Navigation

Action Button(s) Description

Navigate to tabs */* Top left & right softkeys

Navigate to pages 82

Up & down navigation button

Navigate within display (e.g., move highlighted octave band)

4 6 Left & right navigation button

Access content specific menu *** There are times when a content specific menu appears. Press the associated top soft key to

access that menu.

Exit a menu /*/ Press the top-middle soft key to close or save. To exit without saving, press it, and then select No or

Cancel.

Navigate up & down in a display 5 Press the ENTER button to move up and down on certain pages.

Make a selection 5 Press the ENTER button to make a selection.

Table 2.2 Buttons for Basic Run

Action Button(s) Description

Initiate a run 9 Start a measurement

Pause a run 9 While the 831C is running, press this button to pause

Stop measurement 7 End a measurement during a run or pause

Store data file 7 Pressing the stop/store button while the meter is stopped will store the measurement data

Reset measurement 1 Press once to clear unsaved measurement data. Press a second time to reset filters (this may take

a few seconds).

SoundAdvisor Model 831C Display Elements Overview 2-5

The 831C allows for complete operation from the meter itself. Whenyou select a field to enter text, a virtual keypad appears. Use the UP,DOWN , and LEFT and RIGHT navigation buttons tonavigate. Press e to make a selection.

2.3 Display Elements O er iewIn this section:

• 2.3.1 Changing Display Color Themes

• 2.3.2 Using Tabs and Pages

• 2.3.3 About Status Bar Icons and Indicators

• 2.3.4 Main Menu Overview

• 2.3.5 Tools Menu Overview

• 2.3.6 Power Control Menu Overview

2.3.1 Changing Display Color Themes

The 831C has a full-color, back-lit LCD touchscreen and allows you toselect your preferred color theme. The Dark theme is featured in thismanual. For more information, see 9.5.6 Customizing the DisplayColor Theme.

2.3.2 Using Tabs and Pages

The 831C interface is organized into tabs. The Live and Overall tabs arefurther organized into pages that can be accessed using the UP and DOWN navigation buttons. If needed, additional pages ofmeasurement data are available to purchase from Larson Davis.

When the 831C is first powered on, the Live tab (Page 1) is the firstscreen you’ll see. Figure - reviews display elements that are commonto most tabs.

FIGURE 2-3 Live Tab (Page 1)Status bar icons. See 2.3.3 About Status Bar Icons and Indicators.Access the Tools menu

View additional data on pages using the UP and DOWN navigation buttons.

Measurement name of current running measurement

Data display Session Log tab to the left Overall tab to the right.


There are 5 tabs in addition to the Live tab. Press the top-left or top-right softkeys (*/*)to navigate between tabs. Figure -4 shows thenext 2 tabs to the right of the Live tab.

FIGURE 2-4 Navigating Tabs to the Right

Live Tab: Since the Live tab shows active, real-time values that themeter is currently sensing, this page is not controlled by the (RUN/PAUSE) button . This allows you to view the current SPL withoutdisrupting your measured data. You can enable and view up to 13pages of Live data.

Overall Tab: Values on the Overall tab are averaged from the start ofthe measurement up to the current time (Elapsed Time). If themeasurement is stopped, the elapsed time stops. You can enable andview up to 20 pages of Overall data.

Session Log Tab: The Session Log tab displays a record of meteractions during a measurement. The Session Log tab in Figure -4 showsa time-stamped line item for every run, pause, resume, stop, and soundrecording action. The source responsible for each action is alsorecorded. Resetting and storing data begins a new, blank session log.

LEARN MORE For details on each tab, see Module 4 Using the Data Display.

2.3.3 About Status Bar cons and ndicators

The status bar at the top of the screen displays the meter,measurement, connection, alert status, and battery status as shown inFigure - .

FIGURE 2-5 Status BarPower Indicator

USB Memory Status

WiFi Status

OBA Indicator

SLM Indicator

Measurement Runtime

Run Status

File Name


Power IndicatorsBattery Power IndicatorThe battery icon indicates the state of the battery charge by color andvolume. When using battery power, the battery icon indicates the stateof the battery from fully charged to depleted, left to right. The boltsymbol appears over the battery icon if the battery is currentlycharging.

External Power IconThe external power connection icon appears when the 831C is poweredfrom an external power supply or from the USB port.

iFi Status IconSee 13.4 Using iFi On Your 831C SoundAdvisor.

USB Memory Status IconsWhen you insert a USB drive into the 831Cs USB port, the USB driveicon appears in the Status bar of the meter’s display as shown in Figure

- .

If the Data Storage setting is set to USB, but no USB drive is inserted,the USB not available icon appears. Files save to the meter until youinsert a USB drive.

If the USB drive is removed during a measurement, the same iconappears, the measurement ends, and data with that measurement isnot visible on the meter. When the USB drive is reinserted, the USBcaution icon appears. The meter notifies you that there is unsaveddata and prompts you to Save or Delete the measurement data. Youcannot continue with the same measurement.

Input Overload IconWhen a signal from the preamplifier exceeds the calibrated input rangeof the 831C, the Input Overload icon appears. While the overload ispresent, the icon flashes.

When the overload condition resolves, the icon is still present (notflashing) to indicate that an overload has occurred during themeasurement. Press the RESET button to clear the icon from thedisplay.

Under Range IconThe Under Range icon displays in the status bar while an under rangecondition applies. For details about the under range level, see 5.1.2Determining Noise Floor, Overload, and Under Range Levels.


FIGURE 2-6 Under Range vs Normal Range Data Display

OBA Overload IconThe OBA Overload icon displays while the input to the Octave BandAnalyzer is overloaded.

TAKE NOTE When the OBA Range property is set to Normal, the OBA Overload Icon displays at a level 33 dB lower than if the OBA Range had been set to High.

OBA Under Range IconWhen the signal from the preamplifier drops so that the noise level ofthe instrument and the preamplifier influence the measurement, anUnder Range condition exists.

When all filters of the OBA are “under range” the OBA Under Range Iconflashes.

Measurement Status IconsFIGURE 2-7 Measurement Status Icons

Under Range Display Normal Range DisplayValues in an “under range” condition display darkly on the Live tab.

RunA measurement is currently running.StopA measurement is stopped.

ResetA measurement reset has occurred.

Run PendingThe meter is waiting for filters and detector initialization to complete and will automatically start the run when the system is stable (typically less than 10 seconds).

PauseThe present run is paused.


If the touchscreen is enabled, or if you’re operating the meter remotely,tapping the icon produces the following result:

Sleep IconWhen the 831C is not connected to a PC, it can be put in a batterypower saving “sleep” mode that shuts down the analog circuitry,including the preamplifier. In this case, the Sleep icon displays in placeof the measurement status icon.

To learn more about power saving options, see 9.4 Editing PowerSettings.

File Operation IconThe file operation icon appears in the status bar while a file is saved tothe USB, moved from the USB to meter, or copied. All these operationsare done in the Data File Manager.

For more information, see 8.2 Using the Data File Manager.

2.3.4 Main Menu Overview

The 831C main menu contains the following 5 features:

Setup ManagerThe Setup Manager is a menu on the 831C —divided into tabs just likethe 831C main display— that enables you to customize measurementsettings in a setup file or “Setup.” To access the Setup Manager, pressthe Menu soft key, and select Setup Manager.

TAKE NOTE You can also create a setup file using G4 LD Utility, then transfer the file to the meter. For more information, see the G4 LD Utility Manual.

Mark Sound TypeWhen you’ve purchased and installed firmware option 831C-SR or831C-MSR, this feature allows you to assign a Sound Type marker tothe current sound. When you examine the data file after the

Table 2.3 Using the Measurement Status Icon

Measurement State Action Resulting Measurement State

Run Tap Once Stop

Run Double Tap Pause

Pause Tap Once Run

Stop/Reset Tap Once Run

Stop/Reset Double Tap Store

Run Pending N/A N/A

Power Save Tap Once Run


measurement, the marker indicates where that sound type occurredduring the measurement. See 18.1 Setting Up Markers for SoundRecording.

Adjust Graph MenuAllows you to adjust the X and Y on the visual graph when needed. See4.4 Adjusting the Graph Scale.

ResetThis feature operates the same as the Reset button on the meter. Pressonce to clear any unsaved data for that measurement. Press a secondtime to reset filters. Wait a few seconds until filters reset completelybefore making a new measurement.

Locate

Print ScreensOnly available with printer inserted.

2.3.5 Tools Menu Overview

Press the TOOLS 3 button gives you access to the following menusand settings on the 831C.

Data File ManagerAccess all data files on the meter or inserted USB drive. Module 8Managing Measurement Data Files.

CalibrateCalibrate the microphone for accurate measurement. See Module 5Calibrating Your SoundAdvisor 831C.

Setup ManagerSetup measurement parameters and metrics. Module 6 Creating aMeasurement Setup.

System PropertiesAccess properties for the meter, set time, language, and otherpreferences. See Module 9 System Properties.

About Tab: System InformationAccess system information. See Module 10 System Information.

LockLock the meter’s screen to prevent tampering. See Module 11 Usingthe Meter Lock.


System UtilitiesFormat or restore file system. See Module 12 System Utilities.

CommunicationQuick access to communication properties. See Module 13 831CNetwork and Connections.

2.3.6 Power Control Menu Overview

To access the following actions on the Power Control menu, press thePOWER button 0 once.

• Battery Information

• Display Brightness

• Power Off

• Reboot

SoundAdvisor Model 831C Unpacking & Inspecting 3-1

Module 3 etting StartedIn this module:3.1 Unpacking & Inspecting ......................................................................................................3-1

3.1.1 Serial Numbers ......................................................................................................3-2

3.2 Connecting the Microphone & Preamplifier ......................................................................3-2

3.3 Connecting the Preamplifier to Meter ................................................................................3-3

3.4 Disconnecting the Preamplifier .......................................................................................... 3-3

3.5 Powering the 831C SLM ....................................................................................................... 3-43.5.1 Using Battery Power .............................................................................................3-43.5.2 Using External Power ............................................................................................ 3-63.5.3 Understanding 831C Power Usage ......................................................................3-7

3.6 Powering On or Off ..............................................................................................................3-83.6.1 Viewing the Power Control Page Settings ...........................................................3-8

3.7 Operating the 831C Remotely .............................................................................................3-83.7.1 Operating the 831C from G4 LD Utility ................................................................. 3-93.7.2 Operating the 831C from the LD Atlas App ..........................................................3-93.7.3 Operating the 831C from a Web Browser ..........................................................3-10

3.8 Long Term Storage of 831C ...............................................................................................3-10

3.1 Unpacking InspectingTAKE NOTE Report any damage or shortage immediately to PCB Piezotronics, Inc.

See “Contact Larson Davis” on page i-2.

The 831C is shipped in protective packaging. First, verify the shipmentcontains all parts and accessories for the configuration you selected.Retain the packaging for safe shipment for calibration service. a le 1shows the basic contents, and a le shows the 831C-FFconfiguration. Your 831C contents may differ.

Table 3.1 831C asic Contents

SoundAdvisor Model 831C

PRM831 Microphone Preamplifier

377B02 1/2-inch Microphone

CAUTION Sensitive to static electricity

SoundAdvisor Model 831C Connecting the Microphone & Preamplifier 3-2

The 831C-FF and 831C-RI packages should include items in Table 3.1and Table 3.2:

3.1.1 Serial Numbers

The 831C serial number is printed on the back panel label. Themicrophone model and serial numbers are engraved on the outside ofthe microphone. The preamplifier model and serial numbers areengraved on the outside surface of the preamplifier.

We recommend that you record the purchase date, model and serialnumbers for your instrument, preamplifier, and microphone.

3.2 Connecting the Microphone PreamplifierCAUTION DO NOT handle the microphone and preamplifier without observing the following items:

• Ground yourself so the pogo pin is not exposed to static shock.• Never use excessive force.• Gripping tightly or screwing tightly is unnecessary.• Do not remove the microphone grid cap and expose the dia-

phragm.

Table 3.2 831C FF Package

831C-CCS Hard Shell Case PSA029 Universal AC Power Adapter

WS001 3 -inch Windscreen Lanyard

4 AA NiMH Batteries LD USB Drive with

• G4 LD Utility software

• 831C Reference Manual

• Digital Calibration Certificates

SoundAdvisor Model 831C Connecting the Preamplifier to Meter 3-3

FIGURE 3-1 Microphone and Preamplifier

Step 1 Carefully place the bottom of the microphone over the top of thepreamplifier and gently screw the assembly together. The microphonebody should seat smoothly against the preamplifier body.

To disconnect the microphone:• Lightly grip the 2 engraved lines on the microphone

body and gently turn.

3.3 Connecting the Preamplifier to MeterCAUTION Do not attempt to screw the preamplifier onto the 831C.

Step 1 Both the preamplifier and the preamplifier housing on the meter aremarked for correct alignment look for a vertical, engraved line on thepreamplifier, which aligns with the arrow about the button on the 831C.For reference, see Figure - .

Step 2 With the alignment marks on both pieces lined up vertically, insert the 5-pin connector at the bottom of the preamplifier snugly into the top ofthe 831C until you hear a small click.

3.4 Disconnecting the PreamplifierFIGURE 3-2 831C Preamplifier Housing

The bottom of the microphone attaches to the top of the preamplifier. The preamplifier body houses a single gold pin with threads on the top edge, which are designed to fit the 1/2-inch microphone.

CAUTION Do not allow dust or debris to collect in an unassembled preamplifier.

To disconnect the preamplifier, press and hold this button while gently pulling the microphone/preamplifier assembly from the meter.

SoundAdvisor Model 831C Powering the 831C SLM 3-4

3.5 Powering the 831C SLMIn this section:

• 3.5.1 Using Battery Power

• 3.5.2 Using External Power

• 3.5.3 Understanding 831C Power Usage

3.5.1 Using Battery PowerCAUTION Do not mix Alkaline and NiMH batteries. Only charge NiMH bat-teries.

CAUTION Do not mix batteries from different manufacturers, replace all 4 batteries at the same time.

CAUTION When changing batteries, select the correct Battery Type in System Properties. See 9.4.1 Changing Batteries and Editing the Bat-tery Type.

CAUTION Resolve a Session Log entry “Charging Stopped” by checking the batteries, and ensuring the correct battery type is selected in System Properties. Additionally, the battery may be too old to charge. Battery may also be read as an incorrect battery type, which may occur with fully discharged NiMH batter-ies. Use an external battery charger to restore charge, then install in meter. Addi-tionally, the batteries may be too hot or too cold.

CAUTION The 831C is compatible with Energizer, Duracell, and other commercially-recognized brands of these battery types:

• AA nickel metal hydride (NiMH)

• AA Alkaline

• AA 1.5 Volt Lithium

CAUTION Optimal battery temperature is 0° C–45° C.

Current Battery Voltage is displayed on the Power Control page. Toaccess the Power Control page, press the Power button 0.

In the Status Bar section of the meter display, the battery icon indicatesthe state of the battery charge by the color and fill.

Understanding the Low Battery IndicatorAs the battery nears the end of expected life, the empty battery symbolbegins to flash. When the battery is no longer functioning, the 831Cstops running, saves all data and instrument status, then turns off.When you power the 831C is again with fresh batteries or an externalpower supply, the unit returns to the state it was in prior to shuttingdown.

Full Charge Low Charge


Installing BatteriesThe battery compartment of the 831C is on the back of the instrument.When installing batteries, always insert 4 fresh AA batteries, andobserve polarity markings as shown here.

Charging Batteries in the 831CBefore you begin:

• Install batteries as shown in Installing Batteries.

You can charge batteries (NiMH only) in the meter in about 7 hourswhen the meter is turned OFF.

Step 1 On the 831C, press Tools 3 System Properties.

Step 2 Select NiMH as the Battery Type.

Step 3 The Charge drop-down menu is automatically set to On. If you do notwant your power source to charge the batteries, select Off.


Step 4 Select Save, then click Yes to confirm your choice.

TAKE NOTE Batteries charge more efficiently when the meter is powered off. For details about 831C button LED indicators, see “Understanding Charging Status LED Indicators”.

Step 5 Power the meter OFF.

Step 6 Connect the meter (with the USB cable) to the included power cable(PSA029), and plug this in to a wall outlet or other external powersource.

TAKE NOTE If you’re using a power cable other than the one supplied with the meter, use a 28 AWG or larger wire for proper charging.

Understanding Charging Status LED IndicatorsThe charge status indicated by the green LED behind the Power buttonis as follows:

• Solid green: Charging

• No green light: Not charging

• Green light wink: Maintaining charge

• Green light fast blink (two times per second): Charger fault

• Green light fastest blink (three times per second): Meter ispowering up or shutting down

Resolving a “Charging Stopped” Session Log EntryTo resolve a “Charging Stopped” Session Log entry, check the batteryplacement, and make sure the correct Battery Type is selected (Tools System Properties).

Resolving an “Incorrect Battery Type” Session Log EntryInfrequently, when the battery becomes too old to charge, the metermay register the battery as the incorrect battery type. This can alsooccur when newer NiMH batteries are fully discharged. In this case,charge the batteries using an external battery charger, then installthem in the meter.

You may also see this error when the batteries become too hot or toocold. Optimal battery temperature is 0° C–45° C.

3.5.2 Using External Power

We recommend maintaining the internal battery The 831C utilizes thefollowing external power sources:

• USB port from a computer

• USB port from PSA029 power supply

• I/O connector from an external +10.8 to +25 Volt DC mainspower source.


Using USB Port PowerThe 831C can be powered via the mini-USB Type B port with the PSA029external power supply and the included power cable (CBL138). Themini-USB Type B connector is located on the bottom of the meter.

CAUTION If you operate the 831C without batteries and power is interrupted, you may loose your data.

With the PSA029 power supply connected and operating at ratedconditions, the 831C operates properly with or without batteriesinstalled. Use the included cable to prevent excessive power loss.

3.5.3 Understanding 31C Power Usage

Understanding a Low oltage Shutdown EventThe 831C preserves the service life of an external battery by preventingit from being discharged excessively. When the battery voltage dropsbelow the External Shutoff Voltage (default value +10.8 volts) andremains above +10.2 volts for one minute, the instrument stops, savesdata, and turns off.

Understanding a Power On After Power Loss EventWhen the 831C is powered from an external supply and the inputvoltage falls below the indicated External Shutoff Voltage threshold, itpowers off. When the 831C shuts down due to a low battery, itautomatically attempts to power up after a short reprieve. If there’sadequate power, it remains on. However, if the battery is stilldischarged, it powers off. This attempted “power on” cycle continuesuntil the meter has sufficient power to remain on. This feature isdesigned to allow the 831C to automatically restart when power is lostdue to low solar situation or after an extended power outage.

LEARN MORE To learn more about reboot time after a power loss, see “Low Power At Boot-Up” on page A-5.

Understanding a Sudden Loss of External oltage EventWhen the external voltage is suddenly lost—if the external supply isdisconnected or the main power fails and there is no external battery—the 831C continues to run on internal batteries if they are present andin good condition. If battery power is not present, the 831Cimmediately switches to an internal recovery battery and powers downsafely.

Understanding the External Power IndicatorWhen connected to an external power source using the included USBcable, the External Power icon replaces the Battery icon.

If your meter has fully-charged NiMH batteries and is plugged into apower source, this icon indicates that it’s using power from the externalsource, and is not charging or using any power from the batteries.

SoundAdvisor Model 831C Powering On or Off 3-8

Understanding a Low Power At Boot Up EventAt start up, the 831C performs a power check. If the supplied power istoo low, the low power icon displays over top of the first display. Formore information see Table A.3, “Low Power At Boot-Up”.

3.6 Powering On or OffPowering OnPress and hold the ON/OFF button 0 on the meter until the screenflashes and the green LED under the button turns on.

Powering OffThere are 3 ways to power off the 831C:

1. Press the ON/OFF button 0 once to access the Power Control page,then press the top-left softkey to select Off.

2. From any screen, press and hold the ON/OFF button 0 for 3seconds to begin the shut down sequence.

3. Press and hold the ON/OFF button 0 for 10 seconds to force animmediate shutdown. CAUTION Using this method may result in lostdata.

3.6.1 Viewing the Power Control Page Settings

From the Live tab, press the UP button to view your meter’scurrent power settings (Live 8/8).

3.7 Operating the 831C RemotelyOther than direct control on the meter interface, there are 3 ways youcan remotely operate the 831C:

Battery settings display here. You can edit these settings from the Power Control page. For more information, see 9.4 Editing Power Settings.

SoundAdvisor Model 831C Operating the 831C Remotely 3-9

• From a mobile device. See 3.7.2 Operating the 831C from theLD Atlas App.

• From your PC via G4 LD Utility software (G4). See 3.7.1Operating the 831C from G4 LD Utility.

• From the Chrome browser on your PC or mobile device. See3.7.3 Operating the 831C from a eb Browser.

3. .1 Operating the 31C from G4 LD Utility

To operate and manage the 831C from your PC using G4, complete thefollowing process:

Step 1 Provide your meter with any of the following connections to your PC: USBcable, WiFi adapter, TCP/IP, or Bluetooth adapter.

LEARN MORE For more information, see the G4 LD Utility Manual Module 1 Introduction. The manual is available at LarsonDavis.com/G4.

Step 2 Install G4 on your PC.

Installing a. Locate the most recent version by navigating to

LarsonDavis.com/G4 and choosing the version you needfrom the Software section.

b. The G4 installer downloads as a ZIP file to your PC.

c. Extract and install the E E file. G4 creates a shortcut on theDesktop and an item in your Start Menu.

Step 3 Launch G4. Meters using WiFi, USB, or Bluetooth connections mayautomatically display in the Meters Panel on the left.

LEARN MORE For more help connecting your SoundAdvisor, see Module 13 831C Network and Connections.

Step 4 Click the name of your connected meter. This opens the Meter tab.

Recommended Next Steps:• 5.4 Calibrating Your SoundAdvisor 831C

3. .2 Operating the 31C from the LD Atlas App

Step 1 Install the LD Atlas app.

Connected

Not Connected

SoundAdvisor Model 831C Long Term Storage of 831C 3-10

Installing LD Atlas for Mobile DevicesThe LD Atlas app is available for Android from the Google PlayStore 1, or for iOS from the Apple App Store .2

a. Open the app store on your mobile device.

b. Search for “LD Atlas” and follow the prompts.

Step 2 Make a Bluetooth, WiFi, or other connection to your mobile device. Formore information, see Module 13 831C Network and Connections.

Step 3 Launch LD Atlas on your mobile device, then select your active meter inthe meters panel.

3. .3 Operating the 31C from a eb Browser

We recommend using LD Atlas, but if needed you can operate yourmeter remotely by using a web browser.

Step 1 With the 831C, make a secure connection to the Internet. For moreinformation, see Module 13 831C Network and Connections.

Step 2 Open a web browser on a mobile device or PC. We recommend usingChrome.

Step 3 In the address field, type the IP address of your 831C Sound Advisor.

Ex: 198.999.103.25/SoundAdvisor

TRY THIS To find your meter’s IP address go to Tools Setup iFi.

Step 4 Navigate the interface in the browser just as you would from the meter.

3.8 Long Term Storage of 831CCAUTION DO NOT use the hard-ware power switch to turn the 831C OFF. Permanent damage and data loss may occur. Press the Power button once, then select Off.

The Hardware Power Switch on the bottom of the 831C disconnects thebatteries from the 831C hardware (For reference, see Figure - . Thereal-time clock maintains its value while the switch is off. The powerswitch prevents battery drain when the meter is not in use for anextended period of time. If you plan to store the meter for more than 2weeks, remove the batteries.

1. Android is a trademark of Google LLC.2. Apple and iPhone are trademarks of Apple Inc., registered in the U.S. and

other countries. Multi-Touch is a trademark of Apple Inc.

Connected

Not Connected

SoundAdvisor Model 831C Long Term Storage of 831C 3-11

If the switch is in the “ 0 ” position, the batteries are disconnected.After installing batteries be sure to move the switch to the “ | ” position.

SoundAdvisor Model 831C Understanding the Live Tab 4-1

Module 4 Using the Data DisplayThe 831C takes a measurement, and simultaneously displays thatsame information in a variety of ways. Using the 831C tabs (select leftor right) and their associated pages (scroll down and up), you can takea measurement and view the following metrics at the same time:

• Real time sound metrics

• Frequency of sound at each octave

• Leq, LS, LPEAK of the overall or live sound

• Fast and Impulse detectors

• Temperature, GPS, and elevation of the measured sound

• The current sound, weighted for specific values

4.1 Understanding the Live Tab ............................................................................................... 4-14.1.1 About the SLM Page (Live Tab Page 1) ................................................................. 4-24.1.2 About the Big Digit Sound Page (Live Tab Page 2) .............................................. 4-34.1.3 About the Octave Band Analyzer Page (Live Page 3) ..........................................4-34.1.4 About the Normalized Octave Band Page (Live Page 4) .....................................4-34.1.5 About the Triggering Page (Live Page 5) ..............................................................4-44.1.6 About the Preamplifier Interface Page (Live Page 6) ..........................................4-44.1.7 About the Power Page (Live Page 7) .................................................................... 4-5

4.2 Understanding the Overall Tab .......................................................................................... 4-64.2.1 About the Overall SLM Page (Overall Page 1) ......................................................4-64.2.2 About the Overall Big Digit Page (Overall Page 2) ...............................................4-74.2.3 About the Overall Leq Page (Overall Page 3) ....................................................... 4-74.2.4 About the Octave Band Analyzer Page (Overall Page 4) .....................................4-84.2.5 About the Normalized Octave Band Page (Overall Page 5) ................................4-94.2.6 About the Ln Percentiles Page (Overall Page 6) ................................................4-104.2.7 About the Exceedances Page (Overall Page 7) ..................................................4-114.2.8 About the Overloads Page (Overall Page 8) .......................................................4-124.2.9 About the Community Noise Page (Overall Page 9) ..........................................4-124.2.10 About the C Minus A Impulsivity Page (Overall Page 10) ..................................4-134.2.11 About the TA-Lärm Page (Overall Page 11) .......................................................4-144.2.12 About the Sound Exposure Level Page (Overall Pages 12) ...............................4-144.2.13 About the Metrics Matrix Page (Overall Page 13) ..............................................4-144.2.14 Viewing the Power Page (Overall Page 14) ........................................................4-15

4.3 Understanding the Session Log Tab ................................................................................4-16

4.4 Adjusting the Graph Scale .................................................................................................4-17

4.5 Enabling or Disabling Display Tabs ..................................................................................4-17

4.1 Understanding the Live TabWhen the 831C is powered on, the Live tab is the first display you’ll see.Since the values on the Live tab show active, real-time values that themeter is currently sensing, this page is not controlled by the 9 (RUN/PAUSE) button. This allows you to view the current SPL withoutdisrupting your measured data.


Press the UP or DOWN navigation buttons to scroll up ordown through the pages on the Live tab.

LEARN MORE For more information, look for specific terms or labels in the Appendix C

Glossary.

The labels for sound metrics on the 831C are designated byinternational standards. For many displayed values, the frequency andtime weighting are indicated in the name of the metric. For example,LAS is the A-weighted sound pressure level measured using the Slowdetector. Sound pressure level is often referred to as SPL.

TAKE NOTE Depending on which features and options you’ve enabled, your 831C Live tabs may differ from those shown in this section.

4.1.1 About the SLM Page Live Tab Page 1

Page 1 on the Live tab presents a recent history of metrics. You cancustomize the displayed metrics as shown below in this section.

TRY THIS While on the Live (1 of 8) page, press the ENTER 5 button, and select a new “e uivalent” parameter from the pop-up menu.

FIGURE 4-1 Details of the Live Tab Page 1

1.

The duration of the current measurement. This time resets when with an auto-store or a measurement reset.

2.3.

The graph presents the last 120 seconds of the measurement.

1. LAe (1s) is the most recently graphed 1 second value. The frequency weighting for this value, and possibly the detector, corresponds to the metric you select from the Live tab pop-up menu.

2. LAe corresponds to the metric you choose in the pop-up menu on this tab. The default value is LAS.

3. L peak (as shown above) is the current value from the 1s peak detector. The fre-quency weighting (Z in this case) corre-sponds to your Peak selection in the pop-up menu on this tab.


4.1.2 About the Big Digit Sound Page Live Tab Page 2

The big digit display is the easiest to observe both the instantaneoussound level and if the sound exceeds a trigger level that the userdefines.

FIGURE 4-2 Live Tab: Big Digit Display Page

4.1.3 About the Octave Band Analyzer Page Live Page 3TAKE NOTE This feature requires the 831C-OB3 firmware option.

Four pages on the Live tab relate to the octave band setting you choosein the measurement setup (1/1, 1/3, or both). The height of each bandin the graph is the amplitude of sound for that frequency.

FIGURE 4-3 Live Tab: 1/1 Octave Band Page

4.1.4 About the Normalized Octave Band Page Live Page 4TAKE NOTE The normalized octave band page only displays when you enable the

Spectral Ln feature in the measurement setup file.

Current value:Frequency weighting and detector defined from the measurement setup, and updated once per second.

Peak exceedance will gray out if it is under range

Current time on the meter

Each band is one full octave that increases from left to right.

Use the LEFT and RIGHT ( ) navigation buttons to highlight the desired band and the numerical values below will reflect the information at that octave.

Frequency weighting and detector

Frequency band level

The purple band on the far right represents an average sum of all the bands


Similar to the regular octave band pages in display, the normalizedband pages show octave bands (for 1/1 or 1/3) and the numericalvalues of the highlighted band. However, the data is normalized usingthe reference spectra you define at ToolsSystem PropertiesReference Spectra.

FIGURE 4-4 Live Tab: Normalized Octave Band Page

4.1.5 About the Triggering Page Live Page 5

The Triggering page shows when any of the Trigger levels you define inthe measurement setup have been exceeded.

FIGURE 4-5 Live Tab: Triggering Page

4.1.6 About the Preamplifier nterface Page Live Page 6

Use the information on the preamplifier interface page to validate theproper operation of the meter. Figure 4- shows how this page’s displaymay differ, depending on the preamp installed.

Use the RIGHT and LEFT arrow buttons to highlight the bands and change the numerical values.

On this page, pressing ENTER 5 moves this arrow selector between the following options: Ref, Set Reference, and back to the Octave.

View References 1, 2, 3, 4, A, -A, C, and -C

Save the current selected values to use as a reference by selecting Set Reference.

Current live sound

When the SPL1 & SPL2 triggers are exceeded they change from white to orange and red respectively. If sound levels in the

measurement exceed the Peak triggers, the values displayed here turn from white to orange and red respectively.


FIGURE 4-6 Live Tab: Preamplifier Interface Page

4.1. About the Power Page Live Page

The Power page shows the meter status items as shown in Figure 4-7.

FIGURE 4-7 Live Tab: Power Page

Reviewing Battery StatesThe battery will be in one of the following states:

• Estimated battery runtime

• If the meter is being powered by batteries, then an esti-mated runtime will be listed in hours.

• Charger Off

• The batteries are not being charged.

• Charging

Preamplifier currently connected

The voltage of the preamplifier connected is shown in VDC

When a 426A12 is installed this page provides information like temperature and humidity as well as desiccant maintenance information.

The current date and time can easily be seen on this page.

Voltage of the battery and the USB external power source can be tracked here.

Checking the internal temperature of the meter periodically is always good safety practice.

Amount of internal memory available

SoundAdvisor Model 831C Understanding the Overall Tab 4-6

• Batteries are being charged

• Maintain Charge

• Batteries are at capacity

• Low Power Input

• The USB cannot supply power sufficient to charge theinternal batteries.

• Too Hot/Cold

• Batteries are not charging because there is invalid tem-perature range detected for safe charging.

• Over Voltage

• Tried to charge non-rechargeable cells or batteries arefailing

4.2 Understanding the O erall TabThe Overall tab is similar to the Live tab, with an SLM page andsubsequent pages showing sound data. However, the Overall tabshows the data collected from the current measurement. The overalldata resets when the measurement is stopped and saved, or when youpress the Reset button 1.

TAKE NOTE There are other pages of data on Overall tab, which are available to purchase form Larson Davis. Depending on the options and features you’ve enabled, your 831C Overall tabs may differ from those shown in this section.

4.2.1 About the Overall SLM Page Overall Page 1FIGURE 4-8 Overall Tab: SLM Page

Run time of current measurement. This time continues during a pause.

Leq value uses the frequency weighting and detector from the measurement setup file. It is the equivalent sound based on the run time of the measurement.

The data graph presents info from start to finish, left to right respectively.

This SLM metric is customizable. Press ENTER 5 to select a new metric from the pop-up menu.


4.2.2 About the Overall Big Digit Page Overall Page 2FIGURE 4-9 Overall Tab: Big Digit Page

4.2.3 About the Overall Le Page Overall Page 3

FIGURE 4-10 Overall Tab: Le Page

L peak(max)

The highest level the peak detector has measured during the run timeof the measurement. A date and time of occurrence is recorded withthis event. It’s considered the peak hold.

LASmax

The highest level the SPL detector measured during the run time of themeasurement. It’s considered the max hold.

LASmin

The lowest level the SPL detector measured during the run time of themeasurement. A date and time of occurrence is recorded with thisevent.

Leq using frequency weighing and detector indicated

User defined SPL1 Trigger Level and the percentage of time the overall measurement was over the trigger level

Maximum sound level during measurement

Peak level reached during measurement

Time since pause was initiated. The time will accrue each time you pause a measurement.

LAeq and the LAS of the overall measurement

The LZpeak (Z frequency weighting) is the overall reading of the peak detector during the measurement.

These 3 SPL detectors give the date and time when these metrics were met during the measurement.

This run time stops during a pause or stop.


4.2.4 About the Octave Band Analyzer Page Overall Page 4TAKE NOTE This feature requires the 831C-OB3 firmware option, and OBA enabled

in the measurement setup file.

Two pages on the Overall tab relate to the octave band setting youchoose in the measurement setup (1/1, 1/3, or both). The height of eachband in the graph is the amplitude of sound for that frequency. The 1/3Octave band pages are similar, but each band represents a bandwidthof 1/3 octave.

LEARN MORE ust like the Live tab, you can customize the metrics on this octave band page as shown in 4.1.3 About the Octave Band Analyzer Page (Live Page 3).

The Overall tab’s octave band pages show measurement data from thefirst run to the present time. Overall data clears when the measurementis stored, or after you reset 1 the meter. Figure 4-11 shows that thenumerical values on the Octave Band page are color coded to indicate arelationship to the graphed octave band. For example, the blue boxnext to the LAeq data corresponds to the blue bands in the graph.

FIGURE 4-11 Overall Tab: 1/1 Octave Band Page

Table 4.1 O erall Octa e and Colors

Le “Leq” is the average sound level of the highlighted frequency band for the duration of the measurement.


4.2.5 About the Normalized Octave Band Page Overall Page 5TAKE NOTE This feature requires the 831C-OB3 firmware option, and OBA enabled

in the measurement setup file.

FIGURE 4-12 Overall Tab: Normalized Octave Bands

Similar to the OBA Overall Page 4, the normalized octave band pagedisplays numerical values of the highlighted band. The data is then

Lmax Lmax is the maximum sound level of the highlighted frequency band. The maximum spectrum is

determined by the Max Spec setting.

Bin MaxWhen set to Bin Max, it is the maximum value which

occurred during the entire measurement for that frequency band. Since individual frequency bands may reach their maximum levels at different times,

this spectrum might be one which never occurred at any instant during the measurement period.

At MaxWhen set to At Lmax, it is the instantaneous spectrum

at the moment when the broadband maximum occurred (such as LSmax).

Lmin Lmin is the minimum sound level of the highlighted frequency band for the duration of the measurement.

Since individual frequency bands may reach their minimum levels at different times, this spectrum might be one which never occurred at any instant

during the measurement period.

Table 4.1 Continued O erall Octa e and Colors

Highlight the bands to change the selected frequency by using the left and right arrow keys

Press 5 to jump to Ref, Set Reference, and back to Octaves

Set Spectra by selecting Set Reference after making changes to the weighting and reference.

The user defined references are determined by navigating Tools Menu System Properties

Reference Spectra


normalized using the Spectral Ln value you select in the measurementsetup file.

If the frequency components are too small or too large, use the AdjustGraph function described in 4.4 Ad usting the Graph Scale.

FIGURE 4-13 Overall Tab: 1/3 Octave Spectral Ln

4.2.6 About the Ln Percentiles Page Overall Page 6FIGURE 4-14 Overall Tab: Ln Percentiles Page

Table 4.2 Reference Spectra Options

User Defined 1 2 3 4

Positive Frequency Weighting A C

Negative Frequency Weighting -A -C

Ln as a function of frequency for the six user-selected values of n

Frequency at highlighted band

Ln values at highlighted band

LNF50 60.8 dB means that the Fast (F) time-weighted level exceeded 60.8 dB 50% of the time during the measurement.


LEARN MORE For a more in-depth discussion of Ln values, see Ln Value in the en i Gl ary.

An Ln percentile is a statistical measurement of the level that exceeds“n” percent of the time. The statistics are based on the level defined bythe current weighting and detector.

The Ln Percentiles page displays the 6 Ln statistics for themeasurement based on the run time, and the maximum and minimumsound levels measured. You can customize the threshold level in themeasurement setup prior to or during a measurement. For details onthis, see 6.2.2 Customizing Setup Values On the Setup ManagerTabs.

The values of Ln are calculated from an amplitude distribution table,ranging from 0 to 200 dB, in 0.1 dB increments. As a result, it is possibleto calculate Ln values from values of n ranging from 00.01% to 99.99%.

4.2. About the Exceedances Page Overall Page

The Exceedances page has 2 LAS and 3 Lpeak exceedance values. Figure4-1 shows that each time a trigger level is exceeded during a run, thecounter for that level advances, and it displays in orange or red insteadof white.

An exceedance occurs when the level defined by the current weightingand detector exceeds the Trigger Level you set in the measurementsetup. For details on this, see 6.2.2 Customizing Setup Values On theSetup Manager Tabs.

FIGURE 4-15 Overall Tab: Exceedances PageDuring the exceedance After the exceedance

# of exceedances

Time of last exceedance


4.2. About the Overloads Page Overall Page FIGURE 4-16 Overall Tab: Overloads Page

The Overloads page shows the number of times, the percent of time,and the amount of time that the Sound Level Meter and the OBA havebeen overloaded.

LEARN MORE You can find more overload information in 5.1.2 Determining Noise Floor, Overload, and Under Range Levels.

4.2.9 About the Community Noise Page Overall Page 9

The Community Noise page displays the values LDN and LDEN whichare commonly used to evaluate community noise. Since communitynoise metrics are based upon full day measurements, they do notpresent valid data for measurements less than 24 hours duration.

TAKE NOTE The metric CNEL is equivalent to LDEN.

FIGURE 4-17 Overall Tab: Community Noise Page


Metrics shown here are dependent on the number of Day, Evening, andNight hours, which you set in the measurement setup file.

Understanding LDENAlthough the standard ISO 1996-2:2007 specifies default values used inthe calculation of LDEN, in practice the time values defining the day,evening and night periods may be changed, as permitted by Directive2002/49/EC of the European Parliament and of the Council of 25 une2002 relating to the assessment and management of environmentalnoise. It is important to verify prior to measurement that the valueshave been properly defined for your purposes. For help setting thesevalues, see 6.2.2 Customizing Setup Values On the Setup ManagerTabs.

4.2.10 About the C Minus A mpulsivity Page Overall Page 10FIGURE 4-18 C Minus A Impulsivity

The “C minus A” metric provides an indication ofthe low frequency content of noise measured.This is done by subtracting the A-weightedequivalent level from the C-weighted equivalentlevel.

The integrated levels for LAeq are alwayscalculated using the linear detector, regardlessof the value selected in the SLM Setup. The LAIeqvalue is from the impulse detector.


4.2.11 About the TA-L rm Page Overall Page 11FIGURE 4-19 TA Larm

4.2.12 About the Sound Exposure Level Page Overall Pages 12FIGURE 4-20 Sound Exposure Level Page

4.2.13 About the Metrics Matrix Page Overall Page 13

The metrics matrix page shows all the data the meter is alwaysmeasuring in one page. You can use the ENTER 5 button to move thecursor and enable more information for example, if you want to seewhen a peak was measured as shown in Figure 4- 1.

This metric is primarily used in Germany. To turn offthis display, or any other display that is not related toyour measurement, see 4.5 Enabling or DisablingDisplay Tabs.

This page is primarily used for the practice ofindustrial hygiene.


FIGURE 4-21 Metrics Matrix page

4.2.14 Viewing the Power Page Overall Page 14

The power page on the Overall tab shows all records for thatmeasurement, and the status of the meter’s internal memory. This isthe final page on the Overall tab.

FIGURE 4-22 Overall Power Page

Clock icon indicates the time is currently synced with NTP servers.

SoundAdvisor Model 831C Understanding the Session Log Tab 4-16

4.3 Understanding the Session Log TabFIGURE 4-23 Session Log Tab

On the Session Log tab, the 831C creates a time-stamped record forevery meter action, including Calibrate, Run, Pause, Resume, Stop,Voice Message, and Sound Recording, and others. When you store adata file or press the RESET button 1, the session log clears andbegins a new log.

The source responsible for each logged action is also recorded. SessionLog meter actions include the following:

A calibration occurred

The measurement was paused

A run was initiated

There was a time syncHighlight the log entry to see the meter source near the bottom of the screen.

Back-erase occurred

Table 4.3 831C Meter Actions that Create Log Items

ey press Measurement stop

Measurement run Measurement pause

Resume from pause Measurement reset

Calibration record and change Back-erase

Marker set Run timer complete

GPS Time Sync Low battery

Charging stopped Out of memory

Preamplifier connect/disconnect

Create new average

831 INT-ET (Comm Failure) USB Connection detected

NTP Time Sync System time change

SoundAdvisor Model 831C Adjusting the Graph Scale 4-17

4.4 Ad usting the Graph ScaleThe default amplitude (dB) setting for the graphic display of soundpressure level versus time and frequency spectra are as indicated inthis table:

To change the scaling of any one of these graphs, do the following:

Step 1 On the 831C, go to Menu Ad ust Graph.

Step 2 Use the UP, DO N ( ), and RIGHT, LEFT ( )navigationbuttons to select a new Y Max and Y Min.

Step 3 Press the Close softkey (/*/), then select Yes to save your changes.

4.5 Enabling or Disabling Display Tabs

Step 1 On the 831C, go to Tools System Properties.

Step 2 Use the top-right softkey (*//)to navigate to Displays.

Step 3 From the Tabs drop-down, select the tab your option is associated with.

Step 4 Select the checkbox in-line with the options you want visible on themeter.

Step 5 Press Close (*/*), then select Yes to save your changes. Select No toexit without saving.

Table 4.4 Default Settings for the Graphical Display

Level vs. Time Graphs 20 dB to 140 dB

Frequency Spectra, Normal Range 20 dB to 140 dB

Frequency Spectra, Low Range -10 dB to 110 dB

SoundAdvisor Model 831C Understanding the Calibration Process 5-1

Module 5 Calibrating Your SoundAdvisor 831CIn this module:5.1 Understanding the Calibration Process .............................................................................5-1

5.1.1 Determining Microphone Sensitivity ...................................................................5-15.1.2 Determining Noise Floor, Overload, and Under Range Levels ........................... 5-15.1.3 Understanding Calibration Stability .................................................................... 5-2

5.2 Reviewing the Calibration Settings .................................................................................... 5-25.2.1 Calibrate Tab .........................................................................................................5-35.2.2 Calibration Settings Tab ....................................................................................... 5-35.2.3 Calibration History Tab ........................................................................................5-35.2.4 Calibration Certification Tab ................................................................................5-4

5.3 Choosing a Calibrator .........................................................................................................5-5

5.4 Calibrating Your SoundAdvisor 831C .................................................................................5-5

5.1 Understanding the Calibration Process5.1.1 Determining Microphone Sensitivity

The primary role of sound level meter calibration is to establish anumerical relationship between the sound level at the diaphragm ofthe microphone and the voltage measured by the meter so that thesound pressure level can be read directly from the display of the meterin dB. The result of a calibration is the determination of the sensitivityof the meter, including microphone and preamplifier, typically in dB re1V/Pa or mV/Pa.

5.1.2 Determining Noise Floor, Overload, and Under Range Levels

A secondary role of calibration is to determine the sound level whichwould overload the instrument (Input Overload level) and theminimum sound level (Under Range level) that can be accuratelymeasured without being influenced by the operational noise from themeter (Noise Floor).

Noise Floor LevelThe noise floor is calculated as the energy sum of the noise generatedby the microphone, preamplifier, and instrument circuitry. Theappropriate noise floor, and nominal sensitivity compute automaticallyin the 831C with the following preamplifiers and their commonly pairedmicrophones:

• PRM831

• PRM2103

• ICP with ADP074

SoundAdvisor Model 831C Reviewing the Calibration Settings 5-2

Overload LevelWhen using a microphone having a sensitivity of 50 mV/Pa, the inputoverload may occur approximately as shown in Table 5.1.

Under Range LevelThe Under Range level is the higher of the following levels:

1. Noise Floor plus 9.14 dB (under range shown when self noise con-tributes ≥ 0.5 dB to the readings).

2. Actual point where the log-linearity exceeds maximum permitted value. Except for very low noise level microphones, the under range level is usually determined by the noise floor plus 9.14 dB.

LEARN MORE For more information about measurement range, noise floor, linearity range, and max peak levels as they relate to different microphones and Gain settings, see Table A.2 SLM Performance (Nominal Values) on page A-2.

5.1.3 Understanding Calibration Stability

The 831C maintains a stable value of sensitivity over long periods oftime. Significant changes in sensitivity, or a pattern of small but regularsensitivity changes, are indicative of problems with the measurementsystem. To assist you in identifying these situations, the 831C provides2 notifications:

1. Calibration History Table: Data and date/time of the 10 most recent calibrations

2. Large Change Notifications

During calibration, the meter makes an automatic comparisonbetween the sensitivity determined by the calibration and the previousvalue. A warning appears when the difference between these twovalues exceeds 3 dB.

5.2 Reviewing the Calibration SettingsOn your 831C, go to Tools Calibrate.

831C calibration settings display on the following 4 tabs:

• 5.2.1 Calibrate Tab

Table 5.1 Input Overload Levels

Input Gain, dB Overload Level, dB Peak

0 143

20 123


• 5.2.2 Calibration Settings Tab

• 5.2.3 Calibration History Tab

• 5.2.4 Calibration Certification Tab

5.2.1 Calibrate Tab

When you perform a calibration using any of the known preamplifiers,the SoundAdvisor updates the saved calibration information for thatpreamplifier. If you install a different preamplifier, the SoundAdvisorapplies the previously saved calibration information. As long as thesame microphone is being used with that preamplifier, the calibrationis accurate.

5.2.2 Calibration Settings TabFIGURE 5-1 Calibration Settings

5.2.3 Calibration History Tab

Select a log entry and a calibration spectra box appears.

Select a calibrator.The microphone type, sensitivity, and peak overload values are available on this page

The under range and noise floor capabilities.

Select the microphone that is installed on your meter.

Other: If the microphone type is not found, or in special cases, select Other and manually enter the sensitivity.

If your calibrator has unique values, use these fields to manually enter and save them.

Sensitivity data prepopulates based on your microphone. The actual value is calculated during calibration.


FIGURE 5-2 Calibration Spectrum

5.2.4 Calibration Certification Tab

This page documents when the meter was last certified by the factory,and when it is due for recertification.

FIGURE 5-3 Calibration Certification

Every calibration is logged as an event in the Calibration History.

Delta dB is the difference between the level measured during the current calibration and the level from the previous calibration.

Sensitivity is shown in dB relative to 1 V/Pa.

Since space is limited on the meter display, you’ll find a more detailed version of the Calibration History in G4. For more information, see section 1 4 ali rati n i t rie

a in the G4 LD Utility Reference Manual.

The date of the last certification and the due date for the next certification.

The certification interval can be changed to reflect your own certification time line.

A reminder will be displayed as a popup number of days before the interval time has expired.

SoundAdvisor Model 831C Choosing a Calibrator 5-5

5.3 Choosing a CalibratorTAKE NOTE If using a 1/4-inch microphone, the 1/4-inch adapter (ADP024, or

ADP109) is required.

Larson Davis recommends the following calibrator for the 831C:

• Larson Davis Model CAL200: 94/114 dB @ 1 kHz.

The following instances require a correction:

• Using a free-field microphone: For details, see the calibrationdata shipped with calibrator.

• The calibrator and instrument are at a temperature other thanroom temperature (23° C) or not near sea level. For details, seethe calibration data shipped with calibrator.

• Always recalibrate your meter when moving it to anotherlocation (e.g. meter moved to or from 85 kPa static pressureelevation).

5.4 Calibrating Your SoundAd isor 831C

Step 1 On your SoundAdvisor, go to Tools Calibrate.

Step 2 Choose your calibrator from the Select Calibrator drop-down menu.

LEARN MORE Refer to the calibrator’s user guide for more information.

TAKE NOTE For more information on the Other option, see 5.2.2 Calibration Settings Tab.

Step 3 Insert the 1/2” microphone into the 1/2” microphone opening at thebottom of the calibrator.

Step 4 Turn calibrator on. The calibrator turns off after 1 minute. Use it withinthat time, or press the button again.

Step 5 Select Do Calibration. The 831C calibrates and asks if you want to savethe results.

Step 6 Select Yes when complete.

TAKE NOTE If you see an error message (such as Calibration Out of Range), verify that the calibrator frequency on the calibrator matches the calibration frequency on the meter, and perform the calibration again. Be sure to power the calibrator ON each time.

SoundAdvisor Model 831C 831C Setup Manager Overview 6-1

Module Creating a Measurement SetupThe 831C makes measurements based on values indicated in a setupfile (Setup). Setups are created, edited, and deleted on the SetupManager tab. This module describes using the Setup Manager on the831C and in G4, and how to create a custom Setup.

To make a variety of measurements for your specific task, define theproperties of a Setup, including the following values:

In this module:6.1 831C Setup Manager Overview ............................................................................................... 6–1

6.2 Creating a Custom Setup File ................................................................................................. 6–26.2.1 Creating a New Setup File ............................................................................... 26.2.2 Customizing Setup Values On the Setup Manager Tabs ............................... 36.2.3 Choosing a Run Mode ..................................................................................... 76.2.4 Setting Triggers for Exceedances or Events ................................................. 116.2.5 Saving the Setup File .................................................................................... 11

6.3 Troubleshooting a Measurement Setup File ....................................................................... 6–12

6.1 831C Setup Manager O er iewFIGURE 6-1 Setup Manager Tab

Leq, Lmax, Lmin corresponding to user-selected values of frequency weighting and detector

Lpeak and Lpeak(max) corresponding to a user-selected value of frequency weighting

1/1 and/or 1/3 octave real-time spectra Six values of Ln based on 6 user-selected values of the percentage parameter n

Count of the number of times the levels (SPL and Peak) exceed user-selected values

Sound exposure and sound exposure level data

The Active setup determines what the next measurement is based on.

Highlight the Setup you want to view or edit on the Setup Manager tab, then use the top-left and top-right softkeys to access other the settings tabs. Navigate back to the Setup Manager tab to save your changes.

The Default setup, when Set to Active, restores all active properties to factory default values. The Default is a read-only file and can’t be edited or deleted.

Shows the current Setup.

SoundAdvisor Model 831C Creating a Custom Setup File 6-2

The Setup Manager tab shows all saved Setups on the 831C. On this tab,you can activate or edit any setup file in this list. You can also deleteany setup file except for the Active and Default Setups, which persist.

6.2 Creating a Custom Setup FileIn this section:

• 6.2.1 Creating a New Setup File

• 6.2.2 Customizing Setup Values On the Setup Manager Tabs

• 6.2.3 Choosing a Run Mode

• 6.2.4 Setting Triggers for Exceedances or Events

• 6.2.5 Saving the Setup File

While measurement parameters can be indicated directly in the Activesetup, it’s a good practice to save a setup file for each specificmeasurement you perform. Complete all sections of 6.2 to accomplishthis.

6.2.1 Creating a New Setup ile

Before you begin:• Clear the possibility of conflicting settings by setting the LD

Default Setup to Active as shown in 6.3 Troubleshooting aMeasurement Setup File.

Step 1 On the 831C, go to Tools Setup Manager.

TAKE NOTE If the 831C is connected to G4 when you load the Setup Manager, the “Setting in use...” dialog box may appear. If you create a setup or make changes on the meter, refresh the list in G4 to sync your changes and override this message.

Step 2 Highlight the Default setup in the list and press e. This opens theSetup Manager pop-up menu.

FIGURE 6-2 Setup Manager Menu

To activate a Setup, highlight that file on the Setup Manager tab, press e, and selectSet to Active.To create a new Setup, highlight Default, then click Save As to create the new setup file.

You cannot delete or rename the Active or Default Setups.

Click Refresh List to update the Setup Manager tab to reflect any changes you’ve made.


Step 3 Select Save As. This opens the virtual keypad on the 831C.

Step 4 Enter a name for your Setup and select OK. Your setup file appears in theSetup Manager list.

6.2.2 Customizing Setup Values On the Setup Manager Tabs

Before you begin:• Complete the processes described in all previous sections of 6.2

Creating a Custom Setup File.

Step 1 On the 831C, go to Tools Setup Manager.

Step 2 Highlight your setup file in the list, then use the top-left and top-rightsoftkeys to navigate and set values on the tabs as shown in thefollowing figures.

TAKE NOTE Any changes you make with the Active setup selected won’t be saved in your custom setup.

FIGURE 6-3 Setup Manager: eneral Tab

When you select a text field on the 831C, a virtual keyboard appears to enter text.

This value will appear as a filename prefix for all measurement data files saved using this Setup.

Enter up to 250 characters describing the specifics of this measurement setup. The description appears in the downloaded data files.


FIGURE 6-4 Setup Manager: SLM Tab

About Integration MethodsAlthough the 831C measures levels at all 3 detector and frequencyweighting settings, some features require a single combination. Thelevel defined by the detector and frequency weighting you select isused for the computation of Ln, Exceedances, Sound Exposure, andSound Events (when option 831C-ELA, or 831C-MSR is enabled).

The Integration Method setting has 2 options: Linear Integration andExponential Integration. If you’re unsure which to choose, selectLinear. Click on each term to learn more from the en i Gl ary.

FIGURE 6-5 Setup Manager: OBA Tab

Select a Fre uency eighting: (A is the

default), Detector (Slow is the default), and Peak

eighting (Z is the default).

Your choice for the Detector setting communicates to the meter hardware how quickly it needs to begin measuring the current sound. See also Detector in the en i Gl ary

Select the 20 dB Gain checkbox when measuring low level sounds, or when the sound level is near background noise level.

The Running Le Period is used when the Event History option (831C-ELA) is purchased and enabled on your meter. In this example, the period is the Leq of the last 1200 seconds of the measurement run time. For more information, see Module 17 Using Event History.

Normal (107 dB full scale) and High (140 dB full scale) For measurement range specifications, see Table A.6, “Octave Band Analysis 1/1 Octave Linearity Range,” on page 10-A

Select 1/1 Octave bandwidth, 1/3 Octave bandwidth, or both simultaneously.

Choose a Fre uency eight for the 1/1 Octave and 1/3 Octave bandwidth frequency analysis.

Spectral Ln values can be measured using 1/1 or 1/3 octave bandwidths. If both 1/1 and 1/3 are selected in the Bandwidth setting, Spectral Ln only measures for 1/3 octaves.

For more information about Max Spec (Maximum Specification) values, see Bin Max and At Lmax in the en i Gl ary.


When using a microphone having a sensitivity of 50 mV/Pa, the inputoverload will occur approximately as shown in Table 6.1.

FIGURE 6-6 Setup Manager: Control Tab

FIGURE 6-7 Setup Manager: Ln Percentiles Tab

Table 6.1 O A O erload Le els

Input ain dB OBA Range Overload Level dB peak

0 High 143

20 High 123

0 Normal 110

20 Normal 90

The Sound Advisor 831C has 6 Run Modes to control the meter during a measurement. For more information on each run mode, see 6.2.3 Choosing a Run Mode.

Enter any value from 00.01 to 99.99%.

For more information, see ”Ln Value” in the en i Gl ary.

You can edit the Ln values and view the calculated value without stopping or pausing the current measurement.


FIGURE 6-8 Setup Manager: Exceedance Triggers Tab

FIGURE 6-9 Setup Manager: Day/Night Settings Tab

Although the standard (ISO 1996-2:2007) specifies default values usedin the calculation of LDEN, in practice the time values defining the day,evening, and night periods may be changed. This is permitted byDirective 2002/49/EC of the European Parliament and of the Council of25 une, 2002, relating to the assessment and management ofenvironmental noise. Because of these recommendations and theversatility of the standard on this point, it’s important to verify thesevalues prior to making the measurement.

SPL Trigger Levels: When the measured SPL (Slow, Fast, or Impulse) is greater than the trigger level, the exceedance begins. The measured SPL is defined by the current weighting and detector.

Peak Trigger Level: Set 3 peak levels independent of the SPL triggers. Because the peak is associated with Fast detection time, these triggers can identify impulsive noises (e.g., gun shots), which would not normally be measured.

Trigger Levels signal exceedances (and events when Measurement and/or Event History is enabled.)

LDN is the default day/night level. It’s defined by a specific formula as shown in Day-Night Average Sound Level (DNL, Ldn) in the

LDEN is the default day-evening-night level. It’s defined by a formula as shown in Community Noise E uivalent Level (CNEL, Lden) in the


FIGURE 6-10 Setup Manager: (Optional) eather Tab

When you install a weather sensor for the 831C (such as SEN031, orSEN032), the Weather Tab is active in the Setup Manager.

LEARN MORE For more information about weather accessories, view the SoundAdvisor brochure at www.LarsonDavis.com.

Choose your settings as shown in Figure -10. Once you Close and savethe Setup, you can observe the weather readings on the Overall Tab:Weather Page as shown in Figure -11.

FIGURE 6-11 Overall Tab: eather Page

6.2.3 Choosing a Run Mode

Before you begin:• Complete the processes described in the previous sections of

6.2 Creating a Custom Setup File.

This section applies only when weather accessories are connected to the 831C. On the Setup Manager Weather tab, set the eather station type and any other applicable values for the measurement of wind speed, wind direction, temperature and humidity.

If the wind speed is above the Threshold, it is considered windy.

If Excd. Pause is set to Yes, when the wind speed exceeds Excd. Level, sound exceedances are held off.

During a wind exceedance (with sound exceedance paused), the wind speed must drop below the Hysteresis before sound exceedance pause is turned off.

“ indy” indicates the wind speed is 36.8% faster than the Threshold level.

Red line indicates the compass wind direction.


On the Control tab, there are 6 Run Modes available. Your choicedetermines which other settings and features are available. Click on alink below to learn about a run mode.

In this section:• Using Manual Run/Stop Mode

• Using Timed Stop Mode

• Using Stop When Stable Mode

• Using Continuous Mode

• Using Single Block Timer Mode

• Using Daily Timer Mode

Using Manual Run/Stop Mode

Using this mode, you plan to start and stop the measurementmanually. In this mode, the 831C meter preference for Auto-Storedetermines what happens when you stop the measurement.

Step 1 Select Manual Run/Stop from the Run Mode drop-down menu.

Step 2 If desired, enable any additional settings on the Control tab, and move tosection 6.2.4 Setting Triggers for Exceedances or Events.

Using Timed Stop Mode

The measurement is initiated manually, and stops automatically afterthe period you indicate.

Step 1 Select Timed Stop from the Run Mode drop-down menu.

When combined with the Measurement History feature, these 3 modes can be used to create multiple measurement intervals stored in a data file, with new data files created at regular time intervals. For more information, see 15.1 Setting Up a Measurement With Measurement History.

{

Recommended for: When you want to manually control when the meter runs and stops.

Strength: Custom, live measurement

Recommended for: Site surveys

Strength: All measurements have the same duration.


a. Enter the measurement length in the Time (hh:mm:ss) field.


Using Stop When Stable Mode

Step 1 Select Stop When Stable from the Run Mode drop-down menu.

Step 2 Enter values for Delta (dB) and Time as stability parameters. If theparameter is detected, the measurement stops.


Using Continuous Mode

In this mode, when the meter is powered on, a measurement runscontinuously and stores data files according to the Daily Auto-Storevalue you set. If you set Daily Auto-Store to Never, the meter defaultsto your meter preferences for Auto-Store. If a measurement is paused,Continuous mode automatically resumes the measurement after 5minutes.

Step 1 Select Continuous from the Run Mode drop-down menu.

a. Select an option from the Daily Auto-Store drop-down, andenter the time of day the data file should be stored in the Time(hh:mm:ss) field.

TAKE NOTE At the end of the Auto-Store period, the 831C saves measurement record to a new, incrementally-named, data file throughout the day based on the Time (hh:mm:ss). Time indicates the time of day of the first auto store.

TRY THIS If you want to store a data file each hour of the day beginning at 10:05, choose the following settings:

• Auto-Store: 1 h

Recommended for: on-site or off-site control of a measurement

Strength: Measures sound or noise until it changes.

Recommended for: continuous noise measurement

Strength: Totally autonomous; automatic restart in case of power failure.


• Time (hh:mm:ss): 00:10:05

If you press Run at 10:10, the measurement record will store at 11:05,12:05, and so forth. In this case, the initial measurement record willcontain only 50 minutes, while all others will contain the full hour.


Using Single Block Timer Mode

Step 1 Select Single Block Timer from the Run Mode drop-down menu.

a. Enter a Start (y-m-d) date and Time, and an End (y-m-d) dateand Time, where Time is the time of day.

Step 2 If desired, enable any additional settings on the Control tab, and move to6.2.4 Setting Triggers for Exceedances or Events.

Using Daily Timer Mode

Use Daily Timer mode to schedule one or more measurements, whichstart and stop according to the time you set, every day until the Enddate.

Step 1 Select Daily Timer Mode from the Run Mode drop-down menu.


b. If desired, select the checkbox in-line with 2, and 3 to enteradditional measurement periods.

Recommended for: unmonitored measurements

Strength: One measurement automatically starts and stops at the date and time you set.

Recommended for: Work area surveys which follow a worker’s daily schedule and account for breaks.

Strength: Totally autonomous, daily intermittent measurement for long or short number of days.


Step 2 Enable any additional settings on the Control tab, and move to 6.2.4Setting Triggers for Exceedances or Events.

6.2.4 Setting Triggers for Exceedances or Events

When the sound level (defined by the time weight and detector youchoose on the SLM page in the Setup Manager) exceeds the preset level,the meter logs the number of times and the total time the level wasexceeded. These exceedances are reported on the Live Tab TriggeringPage and on the Overall Tab Exceedances Page.

Before you begin:• Complete 6.2 Creating a Custom Setup File.

Step 1 On the 831C, go to Tools Setup Manager, and press the right softkey(//*)until the Exceedance Triggers tab appears.

Step 2 Set the applicable trigger levels.

Step 3 If desired, enable any additional settings on the Setup Manager tabs andmove to section 6.2.5 Saving the Setup File.

6.2.5 Saving the Setup File

Before you begin:• Complete the previous processes beginning with 6.2.1.

Step 1 To save your Setup and exit the Setup Manager, select Close (/*/).

Step 2 In the Save dialog, choose Yes to save the changes you’ve made.

Step 3 Press the Menu softkey (/*/) to return to the Setup Manager Page.

Step 4 Highlight and press ENTER on the name of the custom Setup you created.

Step 5 In the pop-up menu that appears, Set to Active is highlighted. pressENTER to select that option. The next measurements will run accordingto the Setup you just created.

TAKE NOTE You can also complete the setup process in G4 LD Utility, which provides a simple, file transfer-style interface for configuring, saving, and transferring Setup files to your PC or to another meter. To use the Setup Manager in G4, select your meter in the Meters Panel, and click Setup Manager. For more information, refer to the G4 LD Utility Reference Manual at the following location: G4 Help Manuals.

SoundAdvisor Model 831C Troubleshooting a Measurement Setup File 6-12

6.3 Troubleshooting a Measurement Setup FileSetting the LD Default measurement setup as the Active setup can clearthe meter when it’s doing something unexpected and you don’t knowwhy.

Step 1 On the meter, select Menu Setup Manager.

Step 2 Select Default by highlighting it, then pressing e. This opens a pop-up menu.

Step 3 Highlight, select Set to Active, and confirm your choice if required.

Step 4 Press the Close softkey to save the meter settings.

SoundAdvisor Model 831C Before You Start 7-1

Module 7 Making a MeasurementMaking a measurement on the 831C can be as simple as viewing alive reading of the area using the Big Digit display, or as sophisticatedas setting it up with environmental accessories, deploying it in thefield, and logging measurements when the sound level is above 80 dBover the course of many months in all weather conditions. For bothtasks, understanding the basics of measurement making is essential.

Quick Measurement Steps:Step 1 Power On the 831C.

Step 2 Navigate to Overall display.

Step 3 Press Run 9.

Step 4 When finished, press Stop 7.

Step 5 Press Store 7 and save your data file.

In this module:In this module:In this module:In this module:In this module:In this module:

In this module:7.1 Before You Start ...................................................................................................................7-1

7.1.1 Position the 831C .................................................................................................. 7-27.1.2 Performing an Area Sound Field Check ............................................................... 7-3

7.2 Performing the Measurement .............................................................................................7-47.2.1 Pausing the Measurement .................................................................................... 7-57.2.2 Resetting a Measurement .....................................................................................7-77.2.3 Stopping the Measurement .................................................................................. 7-7

7.3 Storing the Measurement ...................................................................................................7-7

7.1 Before You StartBefore performing a measurement, follow these steps to ensure themeasurement is performed properly:

LEARN MORE Each step has a link to the first 6 Modules in the manual, and if read through, will lead to optimal performance of the 831C.


Step 1 Connect preamplifier and microphone to the 831C.For complete instructions, see 3.3 Connecting the Preamplifier toMeter.

Step 2 Turn meter On 0. For complete instructions, see 3.6 Powering On orOff.

Step 3 Navigate to Tools Setup Manager and indicate or check all valuesdesired for your measurement. For complete instructions, see 6.2Creating a Custom Setup File.

Step 4 Calibrate the meter. For complete instructions, see 5.4 Calibrating YourSoundAdvisor 831C.

7.1.1 Position the 831C

The best position for sound recording is to mount the 831C on a tripod.If held in hand, position your body away from and on an angle to themeter to minimize interference of the sound field at the microphoneresulting from body reflections. The microphone should be angledaway from the body.

If using a free-field microphone like the 377B02, the meter should be“pointed” at the sound source being measured.

FIGURE 7-1 Optimal Hand Held Position (Free-Field Mic)

Microphone Extension CableTAKE NOTE Always position the preamplifier/microphone in a way to minimize the

effect of reflections on the sound field near the microphone.

A shielded microphone extension cable may be placed between themeter and the preamplifier/microphone if needed for themeasurement position. No correction is necessary when using Larson

Sound Source


Davis Model EXCXXX microphone extension cables in combined lengthsup to 200 feet. XXX is the length in feet (XXX = 010, 020, 025, 035, 050,060, 100 and 200) available.

WindscreenWind blowing across the microphone generates pressure fluctuationson the microphone diaphragm which can produce errors in themeasurement. As a result, when performing measurements in thepresence of low level airflows, we recommended that you place awindscreen over the microphone and preamplifier. Larson Davisprovides the WS001 windscreen, which is a 3 ½-inch diameter ballmade of open cell foam.

FIGURE 7-2 WS001 Windscreen

7.1.2 Performing an Area Sound Field Check

Starting a measurement during a dramatic sound change can affectyour data in an unwanted way. Before starting any measurement, it’s agood practice to briefly monitor the area sound.

Step 1 On the meter, observe the current sound readings on the Live tab asshown in Figure 7-3.

Because the windscreen canprotect the microphone fromaccidental damage, werecommend using it even whenmeasuring indoors.

SoundAdvisor Model 831C Performing the Measurement 7-4

FIGURE 7-3 Standard Area Sound Before Measurement

LEARN MORE For more detail about the information displayed here, see 4.1.1 About the SLM Page (Live Tab Page 1).

7.2 Performing the MeasurementBefore you begin:

• Charge or provide uninterrupted power for your meter for themeasurement duration. For details, see 3.5 Powering the 831CSLM.

• Create a measurement setup file for this measurement asshown in Module 6 Creating a Measurement Setup.

• Complete an Area Sound Field Check as shown in 7.1.2Performing an Area Sound Field Check.

Step 2 Navigate to Overall on the 831C and press RUN .

eypad LED IndicatorsWhen performing a measurement, the state of the 831C is indicated inseveral ways: measurement state icon, Overall display animation, andthe red and green illumination of the STOP/STORE and RUN/PAUSEkeys.

The time reads 00:00:00.0 on both the Live and Overall displays. (Otherwise the previous measurement was not stored or reset.)

The measurement status icon is set to Stop.

The live sound is steady and within range.

Table 7.1 Measurement State LED Indicators

Measurement State Red LED reen LED

Stopped Winking - - Off

Paused Flashing - - Flashing - -

Running Off Winking - -


LEARN MORE To learn more about the displays and icons, see 2.3 Display Elements Overview.

The Measurement RangeThe measurement ranges over which the 831C meets the standardsdepends upon the selected frequency weighting. Measurements whichinclude levels outside this range should not be considered accurate. Anoverload indication will appear when levels are above the range.However, it isn’t recommended to rely on measurements where thelevels are below the lower limit of the specified range.

Overload As part of the calibration procedure, the overload level (dB Peak)for A,C, and Z weighting is determined for the current instrument setup andmicrophone/preamplifier. When the sound pressure level is higher thanthe calibrated overload level, the input overload icon flashes while thecondition exists.

Under RangeWhen the sound pressure level is lower than the meter’s noise floor (thenoise level of the instrument and the preamplifier), the Under Rangeicon flashes while the condition exists.

.2.1 Pausing the MeasurementTAKE NOTE A measurement may be paused and resumed multiple times.

At any time the measurement of overall data can be temporarilypaused. During a pause, the run clock will not stop and instantaneousdata will continue to be displayed on the Live display.

After a pause, press the RUN/PAUSE key to resume themeasurement. The overall data will not be affected by any acousticevents occurring during the time period that the 831C was paused.

Using the Back Erase FeatureThe 831C has a back-erase feature that allows for a quick erase of thelast 5 to 10 seconds of measured data. This feature is used to erasesounds that are recorded, but not wanted in the overall measurement.

Waiting for valid data to begin

running

Delayed wink

---- Off

Table 7.1 Continued Measurement State LED Indicators

Measurement State Red LED reen LED


Enable Back Erase FeatureThe back erase is visible on the Overall page, when the measurement ispaused, and only after the measurement has run more than 5 secondssince the last run or resume.

The back erase feature is unavailable when any of the following havebeen enabled in the Active setup:

TAKE NOTE Pressing any other key besides the back-erase option will end the back-erase state.

• Measurement History

• Event History

• Spectral Ln

• Event Sound Recording

FIGURE 7-4 Using 831C Back Erase

Session LogThe session log will have an icon to indicate data had been erased.

FIGURE 7-5 Back Erase in the Session Log

The Back Erase feature is located where Menu typically is.

After the first erase, you can erase an additional 5 seconds (not an additional 10).

Undo appears as an option after a 10 second erase.

To close Back Erase, start a run again or Stop the measurement.

Back erase icon will appear when a part of the measurement was erased during a pause.

The amount of time that was erased will be shown in the information box.

SoundAdvisor Model 831C Storing the Measurement 7-7

Time History RecordsThe time history starts from the time the data was restored. The eraseddata will be marked as Back Erase as the record type.

FIGURE 7-6 Measurement Data for Back Erase

.2.2 Resetting a MeasurementCAUTION The measurement data will be lost if not saved. Additionally, saved data will not be lost during a reset.

A measurement often needs to be reset when a radical noise eventtakes place that is unnecessarily recorded in your data. For example, anaircraft passing overhead when attempting to measure the backgroundnoise in a normally quiet area.

CAUTION If a reset happens while a measurement is run-ning or paused, the 831C will automatically stop the mea-surement for the reset, and data will be removed.

To reset a measurement in progress, stop the measurement then pressthe 1 (RESET) key. This will erase all data previously measured andreset the run time clock to zero. A reset will not reset stored data files,only the current run. A reset can be initiated when the 831C is running,paused, or stopped.

.2.3 Stopping the Measurement

The 831C can be stopped during a run or a pause, and will stop the runclock. Resuming a run will continue the overall measurement whichhas been stopped. The run clock will also begin again from the timeindicated when the stop occurred.

7.3 Storing the Measurement

Step 1 Press the Stop button to stop the measurement.

TAKE NOTE You cannot save a file with the same name as a currently saved data file. If you want the new data file to replace the old data file, you will need to rename or delete the old file first. See Module 8 Managing Measurement Data Files.

Step 2 Press the Store button (unless your preferences are set to Auto-store,then the first Stop will store or prompt to store).

Step 3 You will be prompted to save the file. You can change the name of thedata file by highlighting the name and pressing ENTER 5. Thisdisplays the virtual keypad. When finished entering the name, select Yesto save.

SoundAdvisor Model 831C Setting Data File Storage Preferences 8-1

Module 8 Managing Measurement Data FilesEach time you manually or automatically store measurement results,a new data file is created or appended and saved to the location youspecify. While the 831C has 1.8 GB of available internal memory, USB,and cloud storage options are also available.

In this module:8.1 Setting Data File Storage Preferences ................................................................................8-1

8.2 Using the Data File Manager ............................................................................................... 8-28.2.1 Viewing a Measurement Data File ........................................................................8-38.2.2 Using Load Settings ..............................................................................................8-48.2.3 Using Create Average ............................................................................................ 8-4

8.3 Saving, Moving, or Copying Data Files ............................................................................... 8-58.3.1 Setting a Data File Storage Location ...................................................................8-58.3.2 About Data File Naming Conventions ..................................................................8-78.3.3 Moving or Copying Data Files to a USB Drive ......................................................8-7

8.1 Setting Data File Storage PreferencesOn the Meter Preferences page, the Auto-Store and Data Storagesettings allow you to indicate where, when, and how you want themeter to react when a measurement stops and it’s time to store ameasurement record.

Step 1 On your 831C, navigate to Tools System Properties Preferences.

Step 2 Choose an option from the Auto-Store drop-down menu:

Choosing an Auto-Store Meter PreferenceThe Auto-Store meter preference allows you to choose what happenswhen a measurement stops.

• None: All storage must be done manually, unless in thecontinuous daily auto-store mode indicated in a setup.

• Prompt: When you press the 7 Stop button, or a stop occurs,you are prompted to save the measurement data file. Werecommend this setting for manual measurements only.

• Store: A measurement is automatically stored when ameasurement is stopped.

SoundAdvisor Model 831C Using the Data File Manager 8-2

The following Table shows the result of each choice and its relation tothe run mode you choose and a manual or timed stop.

FIGURE 8-1 Preferences Page

LEARN MORE For more information about saving a file to the USB drive see 8.3.3 Moving or Copying Data Files to a USB Drive.

LEARN MORE For more information about enabling SFTP or cloud storage, see 9.12 Setting Up Cloud Storage for Data Files.

8.2 Using the Data File ManagerThe Data File Manager is a directory of all saved data files. Only oneuser at a time can perform actions on data files. If a user is in the DataFile Manager and a another attempts to open it, the second is

Table 8.1 Auto Store Preference and Stop Method

Run Mode Type of Stop Auto Store Preference (Prompt/Store)

Timed Stop Timer final stop Prompts at timer’s end Stores automatically

Manual stop Prompts when stopped Stores automatically

Stop When Stable Timer stop Prompts when stable Stores automatically


Single Block Timer Timer stop Prompts at timer’s end Stores automatically


Daily Timer Timer stop Prompts at timer’s end Stores automatically


Manual — Prompts when stopped Stores when stopped

Continuous Interval stop Follows Daily Auto-Store settings

Manual Prompts when stopped Stores when stopped

Your data file can store to the internal memory, a USB drive, both, or to a cloud storage account.

The Auto-Store meter preference options include: Prompt, Store, None.


prompted to end the first user’s session before they can begin theirown. On the 831C, go to Tools Data File Manager.

FIGURE 8-2 Data File Manager Overview

FIGURE 8-3 Using the Data File Manager Menu

.2.1 Viewing a Measurement Data ile

Step 1 Navigate to Tools Data File Manager.

Step 2 Highlight your desired data file, press Menu (//*), then choose View.This opens a read-only display of the Overall and Session Log tabs,which show that measurement record. To indicate that you are seeing a

A USB drive is inserted, so the USB icon is displayed. The current measurement

can be running, paused, or stopped while viewing data files.

This number refers to the available internal storage unless a USB drive is connected and set for store-only. Then it refers to the USB storage space.

The name includes the Filename prefix you defined in the measurement setup file.

This data file is stored in 2 locations. The top file is saved on the USB drive, and the bottom file is saved on the meter’s internal memory.

1. Highlight a data file.

2. Select Menu (//*).

3. Choose an option from the pop-up Menu. Your choice affects the highlighted data file.

Regarding data files stored on the 831Cs internal memory, you can Rename, Delete, and Delete All Internal Files.

You can also use these Menu items to navigate the data file list: Refresh List,

ump to Beginning, ump to End.


measurement data file and not the live data, the data file icon appearsnext to the data file name.

.2.2 Using Load Settings

From your selected data file, you can load the measurement settingsused to create the selected data file into the Active setup.

Before you begin:• Save your current Active settings to a new Setup file, if needed.

Settings in the Active setup will be lost.

• Stop any measurement currently running or paused.

Step 1 On the 831C, go to Tools Data File Manager.

Step 2 Highlight the desired data file.

Step 3 Press Menu, and select Load Settings from the pop-up menu. (Noconfirmation appears.)

Step 4 Close the Data Manager, go to Menu Setup Manager and confirmsettings in the Active Setup.

.2.3 Using Create Average

Create Average takes a saved data file and adds its average as aninstance to the unsaved Overall measurement.

• CAUTION: Any unsaved measurement will be overwritten withthe new average instance.

• You can add multiple files to the average. Each appears as a newinstance in the overall measurement. However, each file canonly be added once.

• A measurement can run after the averages are loaded. But thisisn’t recommended for averaging purposes.

• After data files are averaged, you can save the new data as asingle file.

Follow these steps to create an average of your data file(s):

Step 1 Navigate to Tools Data File Manager

SoundAdvisor Model 831C Saving, Moving, or Copying Data Files 8-5

Step 2 Highlight the desired data file.

Step 3 Select Menu (//*).

Step 4 Select Create Average from the pop-up menu.

Step 5 Highlight a different data file, and select Menu.

Step 6 Select Add to Average from the pop-up menu.

Step 7 Repeat steps 5–6 until all data files you want to average have been added.

Step 8 Close the Data File Manager and navigate to the Overall display to viewthe average data.

Step 9 To save the averaged data file, press Stop/Store 7.

8.3 Saving, Moving, or Copying Data Files In this section:

• 8.3.1 Setting a Data File Storage Location

• 8.3.2 About Data File Naming Conventions

• 8.3.3 Moving or Copying Data Files to a USB Drive

8.3.1 Setting a Data File Storage Location

Use the meter preferences to indicate where your future measurementdata files should stored. To provide a rough approximation of file sizeand required storage space, the size of a basic measurement data file isabout 42.5 KB.

In this section:• Saving Data to the Internal Memory

• Saving Data to a USB Drive

• Saving Data to USB Backup

• Saving Data to SMTP or Cloud Storage

Saving Data to the Internal MemoryOn your 831C, go to Tools System PropertiesPreferences.

When you select Internal, data files saved manually and via auto-storesave to the meter’s 1.8 GB internal memory. Depending on the contentand frequency of your measurements, this internal memory mayquickly fill.


About the Out of Memory Error When the amount of remaining internal memory reaches 10 MB, inorder to ensure that all measured data can be stored, the 831C stopsautomatically. If the unsaved data is less than 800 kB, press the Stop/Store button 7 to save it. Before you begin another measurement,download all data to an external drive or PC by using the Data FileManager or G4 LD Utility.

• For information about copying files to USB, see 8.3.3 Moving orCopying Data Files to a USB Drive.

• For information about moving internal files to a PC via G4, seethe G4 LD Utility Manual.

Saving Data to a USB DriveOn your 831C, go to Tools System PropertiesPreferences.

When you select USB from the Data Storage drop-down menu, datafiles saved manually and through auto-store save to the inserted USBdrive. If there’s no USB drive in the 831C, the USB not available icondisplays in the Status bar, and data files save to the 831C internalmemory.

Saving Data to USB BackupOn your 831C, go to Tools System PropertiesPreferences.

When you select USB Backup from the Data Storage drop-down menu,data files save to both the 831C internal memory and the inserted USBdrive as a backup copy. If the internal memory becomes full, data filessave to the USB drive. (See About the Out of Memory Error)

Saving Data to SMTP or Cloud StorageSee 9.12 Setting Up Cloud Storage for Data Files.


.3.2 About Data ile Naming Conventions

In addition to manually naming a data file, there are 2 conventions the831C uses to automatically generate unique file names. These are aproduct of the run mode indicated in a setup. a le contains detailsand examples.

LEARN MORE For more information on continuous auto store, see section 6.2.3 Using Continuous Mode.

.3.3 Moving or Copying Data iles to a USB Drive

Complete this section to move or copy a data file from internal memoryto a USB drive.

Step 1 Insert a USB drive in the 831C. Wait for the USB icon to appear inthe meter Status bar (about 10 seconds).

If the Data Storage setting is set to USB, but no USB drive isinserted, the USB not available icon appears. Files save to theinternal memory until you insert a USB drive.

Table 8.2 Data File Naming Con entions

Run Mode File Naming Convention Example Additional Information

Manual Stop “Default Data File”.NNN 831 Data.001 The “Default Data File” can be changed on the General setup page. NNN represents single digits that increment sequentially from 001–999, then reset to 001 to create a unique filename.

Continuous-Up to 48 daily auto-

stores per day (choose a period: range from every 24 hr–30 mins)

YYMMDD .LDO 18031401.LD0 The filename is 12 characters and includes the year, month, and day followed by 2 digits. The values of increment from 00 –99 to create a unique filename.

Continuous- StoresEvery 15 mins or 10

mins

YYMMDD .LD0 1610110A.LD0 The filename includes the year, month, and day followed by a hexadecimal number that increments from 00–FF to create a unique filename.

Continuous- Stores every 5 mins, 3 mins,

or 2 mins

YYMMDD .LD0 181205AA6.LD0 Filename is 13 characters: the year, month, and day followed by 3 alphanumeric values that increment from 000–FFF to create a unique filename.


Step 2 Go to Tools Data File Manager.

Step 3 Highlight the desired data file, and press Menu (//*).

Step 4 Select one of the following actions from the pop-up menu:

• Copy File to USBThe data file will be copied onto the USB drive. The original filewill remain saved on the 831C.

• Move File to USBThe original data file moves from the internal memory to theUSB drive.

• Copy All Internal to USBCopies of all data files on the 831C are saved to the USB drive.The original data files remain saved in internal memory.

• Move All Internal to USBAll original data files move from the internal memory to the USBdrive. The internal memory is blank.

Step 5 Examine the Data File Manager to confirm the desired action.

TAKE NOTE If the USB drive is removed during a measurement, the USB not available icon appears, the measurement ends, and data with that measurement is not visible on the meter. When the USB drive is reinserted, the USB caution icon appears. The meter notifies you that there is unsaved data and prompts you to Save or Delete the measurement data. You cannot continue with the same measurement.

SoundAdvisor Model 831C Setting Instrument Identification 9-1

Module 9 System PropertiesThis module is a reference for 831C system properties and settings.You can also adjust 831C system properties in G4. For moreinformation, see section A.2 in the G4 LD Utility Manual.

In this module:9.1 Setting Instrument Identification ....................................................................................... 9-1

9.2 Updating the Meter Time ....................................................................................................9-1

9.3 Using NTP to Sync the Meter Clock .................................................................................... 9-2

9.4 Editing Power Settings ........................................................................................................9-3

9.5 Setting Meter Preferences ...................................................................................................9-6

9.6 Setting Localization Options ..............................................................................................9-7

9.7 Setting Options On the Displays Tab .................................................................................. 9-8

9.8 Enabling or Disabling Options ............................................................................................ 9-9

9.9 Setting Network Preferences ..............................................................................................9-9

9.10 Setting Up Alert Notifications .............................................................................................9-9

9.11 Setting System Alert Notification Details .........................................................................9-12

9.12 Setting Up Cloud Storage for Data Files ...........................................................................9-14

9.13 Utilizing the Logic In, Logic Out Feature ..........................................................................9-15

9.14 Setting Reference Spectra ................................................................................................9-16

9.15 Generating an App Password ...........................................................................................9-17

9.1 Setting Instrument IdentificationOn your 831C, go to Tools System PropertiesDevice.

Enter 30 characters per field of device information that will appear onthe Tools About page and in alert notifications.

9.2 Updating the Meter TimeOn your 831C, go to Tools System PropertiesTime.

SoundAdvisor Model 831C Using NTP to Sync the Meter Clock 9-2

There are several ways that you can update the time on the meter: byusing GPS, NTP servers, PC clock, or by manually setting the time. Thispage is designed to be manually updated. However, when your timezone is set accurately, the time automatically updates for DaylightSavings time.

FIGURE 9-1 Set Date/Time & Timezone

TAKE NOTE To sync the 831C with the time on your PC, go to G4 LD Utility Meter Manager Maintenance tab. For more information refer to the G4 LD Utility Reference Manual.

9.3 Using NTP to Sync the Meter ClockThe 831C communicates with NTP servers to sync the internal clockwith the most accurate time. This requires a valid Internet connectionthrough Ethernet, wireless modem, or WiFi.

Before you begin:• Set the correct Time Zone (Menu System Properties

Time).

Step 1 On the meter, go to System Properties NTP.

Stop the measurement before setting time, otherwise the time waits to update until the next Stop.Set your time zone first

then select Save.

If you have NTP time it is not necessary to set this. If you want to manually set time and override any syncing, adjust this and select Set Time.

Close and select Yes to save your changes.

SoundAdvisor Model 831C Editing Power Settings 9-3

Step 2 Enter the Primary and Secondary NTP Time Servers.

FIGURE 9-2 NTP Servers

When your time is successfully synced with NTP servers, the NTP iconappears in-line with the current time on the Live and Overall tabs.

9.4 Editing Power SettingsOn your 831C, go to Tools System PropertiesPower to edit thefollowing settings (click on a section below to learn more):

• 9.4.1 Changing Batteries and Editing the Battery Type

• 9.4.2 Setting Auto-Off

• 9.4.3 Using Analog Power-Save Mode

• 9.4.4 Setting the Backlights On Period

• 9.4.5 Enabling or Disabling the Keypad Backlight

• 9.4.6 Setting the External Shutoff Voltage

FIGURE 9-3 Power tab

9.4.1 Changing Batteries and Editing the Battery Type

On your 831C, go to Tools System PropertiesPower.

If you’ve synced with NTP and lose the Internet connection, the 831C attempts to reconnect to servers for up to 2 ½ hours. During this time the NTP icon persists. If the servers cannot be reached after that time, the 831C stops trying to reconnect and the NTP icon is removed.

Set your Battery Type and Charge preference each time you change batteries to prevent damage or fire.


When changing batteries, the Battery Type must match the type ofbatteries you’re installing. The 831C can be powered by alkaline, 1.5Vlithium, or nickel-metal hydride (NiMH) batteries.

CAUTION Do not mix alkaline and NiMH batteries.

CAUTION Do not mix batteries from different manufacturers.

CAUTION Do not replace only 1, 2, or 3 batteries. Replace all 4 batteries when installing fresh cells.

CAUTION Do not change the batteries without also setting the Battery Type (as shown in this section). To prevent serious damage, injury, or fire, edit the Battery Type setting each time you install a different type of battery. When the battery type is set to NiMH, the internal charger is enabled. This can result in fire or injury with alkaline or lithium batter-ies.

Step 1 On your 831C, go to Tools System Properties.

Step 2 Press the top-right softkey until the Power tab appears.

Step 3 Select the Battery Type that matches the batteries you’re installing.

Step 4 Install 4 new batteries. For details, see 3.5.1 Using Battery Power.

Step 5 If you’ve installed NiMH batteries and want to charge them in the meter,enable the Charging feature.

Enabling Charging for NiMH Batteriesa. From the Charge drop-down, select On.

b . Use the included USB cable to connect to a wall outlet. For bestresults, turn the meter off while charging.

LEARN MORE For battery power and usage details, see 3.5.1 Using Battery Power.

9.4.2 Setting Auto-Off


Auto-Off is the period the instrument stays on with no activity. Any ofthe following actions keep the meter on and restart the Auto-Offperiod:

• Button press

• Running a measurement

• USB communication

• Remote communication

Pressing the 0 (ON / OFF) key returns the instrument and the displayto the state it was in when the Auto-Off time expired.


9.4.3 Using Analog Power-Save Mode


Power-Save mode is indicated by the sleep icon . When the meter isnot running, this mode can significantly conserve battery power, sinceit shuts down the meter’s analog circuitry and signal processingactivities.

From the Power-Save drop-down menu, select the period theinstrument should stay powered after a measurement has stopped.

The analog circuitry, including power to the preamplifier, shuts downwhen the instrument is stopped for the period you chose. Performing acalibration, a reset, or starting a measurement restores power. Themeter can run the measurement after a short 10 second power-up.

9.4.4 Setting the Backlights On Period


Backlights On is the duration the 831C display is back lit after the lastkey press. Selecting Always slightly increases power consumption.

9.4.5 Enabling or Disabling the Keypad Backlight


The blue LEDs under the keypad can be enabled or disabled accordingto your preference. The Red LED behind the STOP/STORE button, andthe green LEDs under the RUN/PAUSE and ON/OFF buttons are alwaysenabled.

TAKE NOTE Increasing the back light brightness significantly increases the meter’s power consumption, which decreases battery life.

Additionally, you can select the LCD screen back light intensity as apercentage.

When battery life is below 10%, the 831C overrides this setting anddowngrades the LCD Brightness to 50%. If the user-defined setting isbelow 50% brightness, it remains the same.

9.4.6 Setting the External Shutoff Voltage


If desired, you can customize the external shutoff voltage. When thevoltage of an external battery drops below this value, the 831C shuts offto prevent damage to the external batteries.

LEARN MORE The default voltage is 10.8 volts. To customize this setting, enter a value between 10–25 volts if your battery usage is other than a standard 12V SLA battery. For more information, see Table A.3 on page 5.

SoundAdvisor Model 831C Setting Meter Preferences 9-6

9.5 Setting Meter PreferencesOn your 831C, go to Tools System PropertiesPreferences to editthe following settings (click on a section below to learn more):

• 9.5.1 Setting a Microphone Correction Value

• 9.5.2 Enabling or Disabling AC Output

• 9.5.3 Enabling the Reset Prompt

• 9.5.4 Setting the Data Storage Location

• 9.5.5 Enabling GPS Mode

• 9.5.6 Customizing the Display Color Theme

9.5.1 Selecting a Microphone Correction

The 831C can automatically apply corrections to a measurement toaccount for an environmental shroud or a specific microphone asshown in this section.

Step 1 On your 831C, go to Tools System PropertiesPreferences.

Step 2 Select a option from the Mic Correction drop-down menu.

For Mic Correction options, the 2 characters before the colon representthe physical mic type. The 2 characters following the colon representthe desired response.

For example: if my mic is a free-field mic in an EPS2116 with anenvironmental protection device and I want a 90 degree response, Iwould select FF:90 2116.

Table 9.1 Microphone Correction Options

Option Current Microphone Simulates

Off No Correction

RI:FF Random Incidence Free-Field

FF:RI Free-Field Random Incidence

FF:RI 2016/8 Free-Field with EPS2106 Random Incidence

FF:FF 2016/8 Free-Field with EPS2106 Free-Field

FF:90 2016/8 Free-Field with EPS2106 90-degree measurement

FF:RI 2116 Free-Field with EPS2116 Random Incidence

FF:FF 2116 Free-Field with EPS2116 Free-Field

FF:90 2116 Free-Field with EPS2116 90-degree measurement

SoundAdvisor Model 831C Setting Meter Preferences 9-7

9.5.2 Enabling or Disabling AC OutputFIGURE 9-4 831C AC/DC Output

On your 831C, go to Tools System PropertiesPreferences.

The AC/DC Output is a full dynamic range AC/DC output that can beturned On or Off. The AC continually receives samples from the ADC. Ithas output while the ADC is on and stops during power-save. The DClevel is your configured Lωτ level while running.

The AC/DC output does not drive a headset or headphones.

9.5.3 Enabling the Reset Prompt

On your 831C, go to Tools System Properties.

Whenever you make a measurement that you don’t want to keep, pressthe 1 Reset button to clear the unsaved data. When you select thecheckbox in-line with Reset Prompting, the meter requires you toconfirm your choice before clearing the data. We recommend enablingthis feature.

9.5.4 Setting the Data Storage Location

Use this feature to indicate where your data files are stored. On your831C, go to Tools System PropertiesPreferences.

LEARN MORE See 8.3 Saving, Moving, or Copying Data Files.

9.5.5 Enabling GPS Mode


If you want to attach a GPS device through the Aux port, select On fromthe GPS Mode drop-down.

9.5.6 Customizing the Display Color Theme


SoundAdvisor Model 831C Setting Localization Options 9-8

The 831C LCD screen has 6 color theme options: 3 light and 3 dark. Werecommend the light screens when you’re operating the meter insunlight or outdoor settings. We recommend the dark themes forindoor or low-light use.

FIGURE 9-5 Available 831C Color Themes

9.6 Setting Localization OptionsTo access these settings on the meter, go to ToolsSystemPropertiesLocale.

Selecting a LanguageThe 831C has a built in language translation feature, and you can setyour language preference.

The following languages are available: English, French, German, Italian,Portuguese (PT & BR), Norwegian, Spanish, Swedish, Czech, Turkish,Chinese, and Thai.

Selecting a Decimal SymbolDepending on your preference, select a period or a comma for thedecimal place, and save your change.

Selecting a Date FormatSelect one of the 2 available date formats: dd-mm-yyyy and yyyy-mm-dd. For example: 2017-02-14. Save your change.

Setting a Unit of MeasurementThe default unit of measurement for the 831C is SI (InternationalSystem of Units). However you can also select English units. Make yourselection and save the change.

9.7 Setting Options On the Displays TabTo access these settings on the meter, go to ToolsSystemProperties Displays.

Customizing the Start DisplayStart refers to the display that you see when you boot up the 831C.Select your option from the drop-down, save, and close. Your new startdisplay appears on the next power up.

SoundAdvisor Model 831C Enabling or Disabling Options 9-9

Customizing Tab & Page DisplaySelect an option from the Tabs drop-down menu, then select thecheckbox in-line with items in the Pages list that you want to display.Deselected pages are hidden not deleted.

FIGURE 9-6 Display Options

9.8 Enabling or Disabling OptionsTAKE NOTE Default options don’t appear in the list since they cannot be disabled.

Step 1 On your SoundAdvisor 831C, go to Tools System Properties.

Step 2 Press the top-right softkey until you see the Options Screen.

Step 3 Select the checkbox in-line with the options you want available in the831C interface.

TAKE NOTE Disabling an option in this section does not delete the option. You can select it again at anytime.

Step 4 Reboot the meter.

9.9 Setting Network PreferencesSee 13.3 Setting a Static IP Address.

9.10 Setting Up Alert NotificationsThe 831C can be set up to send email and text alerts for a variety ofsystem events, as well as measurement and sound events by using theSystem Properties email preferences. When an event (setting change,exceedance trigger, sound event, etc) occurs and the meter has anactive network connection, the meter sends the alert notification afterthe event has concluded.

To set up alert notifications for system-, event-, and measurementhistory-triggered events, follow these steps:

SoundAdvisor Model 831C Setting Up Alert Notifications 9-10

Before you begin:• Create an email account on an email server that supports

secure email.

• We recommend that you use 2-Step Verification when usingGoogle. If you choose this option, see 9.15 Generating an AppPassword.

• To avoid spam filters, add the host email addresses to yourcontact list.

• When the meter is configured with a static IP address, you willneed to configure your network settings as shown in 13.3Setting a Static IP Address.

Step 1 Navigate to Tools System Properties Email.

Step 2 Enter a Hostname for your mail server and a Username and Passwordfor your mail account.

FIGURE 9-7 Email Preferences Screen

Step 3 Select the Security level for the account.

TLS Trusted CA (preferred)The 831C matches responding server with a provided certificate toverify that the responding server is known. If the responding servercan’t be verified, the email will not send. Most email providers (such asGmail) use this type of security.

To (Text) field sends a plain text email, or text message (when configured for the following mobile carriers:

AT&T: [email protected]

T-Mobile: [email protected]

Sprint: [email protected]

Verizon: [email protected]

Virgin Mobile: [email protected]

SoundAdvisor Model 831C Setting Up Alert Notifications 9-11

TLS OnCertain configurations use their own method for validating that anemail server is the correct server—such as the US military. Use thissetting when instructed by your IT department.

TLS OffThis is option uses only a login name and password to access an emailserver. This method is not secure, and we don’t recommend it.

Step 4 If desired, enter a Reply-to email address. This is displays as the “From”address in the alert notifications. If someone replies to an email from831C, this is where the email will send.

Step 5 Indicate the To (Email) where you want to receive HTML-based emailnotifications.

Step 6 In the To (Text) field, enter an email address or SMS-enabled phonenumber where you want to receive text notifications. See Figure 9-7.

Step 7 Click Send a Test Email.

If you don’t receive a notification within a few minutes of initiating atest, check to see if your meter is connected to the Internet. Also, makesure a proxy is not filtering your email.

For additional questions or troubleshooting, contact your local ITsupport.

Step 8 Click Close (/*/) to save your settings and exit the menu.

9.10.1 Enabling Alert Notifications for Sound Events

Step 1 Create an Event History-enabled measurement Setup as shown in section17.1 Setting Up the Event History Measurement.

Step 2 Enable notification alerts in the Setup, and make it the Active setup. Formore information, see 17.1 Setting Up the Event HistoryMeasurement.

TRY THIS With firmware option 831C-MSR, or 831C-SR installed, you can also choose sound recording settings in your measurement setup file. To send a sound recording of the exceedance (in WAV or OGG format), go to Tools Setup Manager Sound and select Save Event Sound. For the full process, see 18.3 Making an Automated Event Sound Recording.

Step 3 Run a measurement and trigger an event.

TAKE NOTE The alert notification sends after the event and any continuation period passes. The arrival time of the notification may also be impacted by Internet performance.

SoundAdvisor Model 831C Setting System Alert Notification Details 9-12

FIGURE 9-8 Example Sound Event Alert Notification Email

9.11 Setting System Alert Notification DetailsIn this section, select which details you want to include in the alertnotification.

Before you begin:

• Complete the process shown in 9.10 Setting Up AlertNotifications.

Step 1 On your 831C, go to Tools System Properties Alerts and select fromthe following options:

SettingsWhen you change any setting or preference on the meter, the 831Csends an alert notification.

MemoryThe 831C sends an alert notification when the primary memory storage(free space) is 25%, 10%, and 0%. Primary memory storage can be

HTML alert notification emails send with theevent sound recording as an attachment, unlessone of the following conditions applies:

• Event sound recording is disabled.

• The current sound recording is still beingcaptured when the event ends.

• The event sound recording is too large toattach to the email.

SoundAdvisor Model 831C Setting System Alert Notification Details 9-13

internal or USB. For information about setting the primary memorystorage location, see9.5 Setting Meter Preferences.

TemperatureAn alert notification will be sent when the internal temperature of themeter is outside of 70°C and -40°C.

PowerThere are 4 available alert notifications:

• Low external power: sent when power reaches External ShutoffVoltage + 0.6 V (manually set on “Editing Power Settings” page)

• Meter is shutting down due to low external battery: sent 4seconds prior to shut down

• Power from mains (AC or solar power) is lost, and meter isrunning on external battery for more than 30 minutes

• If power lost alert is sent, then power is restored to mains for atleast 3 minutes, an alert will be sent

Run StateThis alert replaces the SLM State alert. It sends a notification for eachRun, Stop, Pause, or Reset on the meter.

CertificationYou can send an alert notification during the meter’s startup if thecalibration date is expired, or if the reminder for calibration is due. Thisalert occurs once every 24 hours, when enabled.

LEARN MORE For more information, see 5.2.4 Calibration Certification Tab.

Clear QueueThe 831C often queues alert notifications to send at a later time if thenetwork connection is lost, etc. If you don’t want these oldernotifications to send, click the Clear Queue button to delete them.

SoundAdvisor Model 831C Setting Up Cloud Storage for Data Files 9-14

FIGURE 9-9 Alert Notification Email Example

Spam and Duplicate AlertsTo protect recipients from receiving duplicate alert notifications for thesame trigger when the state of the meter fluctuates around that trigger,the 831C has a hysteresis, or threshold, for multiple notifications thatconcern these specific alert details:

• Memory: If a notification is sent, free memory space can raise upto 5% of the trigger level before another alert can be sent.

• Temperature: If a notification is sent, the temperature can riseabove the trigger (-40°C) or fall below the trigger (70°C) multipletimes until the temperature rises/falls at least 5°C. If the sameconditions are met again, after that, another alert notification issent.

• Low external power: After an alert is sent, the voltage can riseup to 0.5 V before another alert can be sent if the conditions aremet.

9.12 Setting Up Cloud Storage for Data FilesWhen a measurement data file is automatically or manually saved, youcan save it on the meter, to a USB drive, or upload directly to a remotestorage service such as Dropbox1 or an SFTP account. You can also

1. Dropbox is a registered trademark of Dropbox, Inc. in the US and other countries.

SoundAdvisor Model 831C Utilizing the Logic In, Logic Out Feature 9-15

receive an alert notification via email or text when a file is saved toCloud storage.

On the meter, cloud storage is managed on the System Properties Cloud Storage tab. However, the initial cloud storage setup must becompleted by using the Setup Manager in G4 as shown section A.3 inthe G4 LD Utility Manual.

9.13 Utilizing the Logic In, Logic Out FeatureThe 831C can receive input from an external device which can initiate avariety of actions.

Logic InTAKE NOTE The CBL170 I/O Interface Cable can be used to make an electrical

connection to external devices. For pinout information, see “I/O Connector Pinouts” on page A-4.

The Logic Input line receives a signal from an external device, which isusually connected using the included CBL170 I/O Interface cable. Thedevice connected through the Logic Input can initiate one of thefollowing actions by an external trigger:

Run/Stop EventA measurement run or stop can be initiated when the Time History(831C-ELA) option is installed and enabled on your meter.

Marker With the Time History (831C-LOG) option installed and enabled for thatmeasurement, Marker #1 will be initiated for the Recording Timeindicated in the Setup, even if there is no sound recording. If soundrecording is enabled for Marker #1, a sound recording also occurs atthis time.

Logic OutThe Logic Out line transmits a signal to an external device, defining oneof these states:

Run StateWhen the Logic Out is set to Run State, then the output will be drivenhigh when the 831C is running and will be driven low when it isstopped.

EventFirst, install and enable the Time History option (831C-ELA) on yourmeter. When Logic Out is set to Event, the output is activated with anevent trigger.

SoundAdvisor Model 831C Setting Reference Spectra 9-16

LEARN MORE To learn more about defining event triggers, see 17.1 Setting Up the Event History Measurement.

MarkerFirst, install and enable the Time History option (831C-ELA) on yourmeter. When a marker is initiated, the output is activated for theRecording Time as indicated in the setup.

9.13.1 Choosing Heater Options

If a heater is detected as part of a preamp, select your preference forthe heater Control:

• Enabled: The heater automatically turns on or off according tothe humidity and ambient temperature as shown in Figure 9-10.We recommend using this setting.

FIGURE 9-10 Recommended Heater Settings

• Timer: Turns the heater on and off automatically according tothe Start Time (24-hr time) and End Time (24-hr time) you sethere.

• Off: The heater remains off.

9.14 Setting Reference SpectraWhen you view the normalize octave band data, you have the option tochoose a negative or positive A or C weighting, or you can define up to 4unique reference spectra. You can view these references in the Liveview (see 4.1.4 About the Normalized Octave Band Page (Live Page4)), the Overall view (see 4.2.5 About the Normalized Octave BandPage (Overall Page 5)), and in the Overall OBA page. See 4.2.4 Aboutthe Octave Band Analyzer Page (Overall Page 4).

Heater Control100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%-10 0 1 2 3 4 5 6 60

T e m p e r a t u r e ( C )

Hum

idit

y

High

Low

Off

SoundAdvisor Model 831C Generating an App Password 9-17

FIGURE 9-11 Set Reference Spectra

9.15 Generating an App PasswordOnce you set up the App Password, you will not need to log in each timeyou want to connect to your mail account. An app password is a 16-digit pass code that gives a non-Google app or device permission toaccess your Google account.

Before you begin:• Set up 2-Step Verification on your account.

Step 1 Log in to your Google account. You can also access your Google Accountby logging in to your Gmail account.

Step 2 On the top navigation panel, choose Security.

Step 3 On the “Signing in to Google” panel, choose App Passwords. If you don’tsee this option:

• 2-Step Verification is not set up on your account

• 2-Step Verification is set up for security keys only

• Your account receives verification through work, school, oranother organization and can’t use this feature

• You’ve turned on Advanced Protection for your account

Use any of the navigation buttons to highlight a band. Press 5 enter to bring up the keyboard to define that octave.

This drop-down takes you to all four 1/1 Octave and four 1/3 Octave band options, where you can indicate the frequency for each selection.

Selecting Name allows you to rename any of the user-defined reference spectrum.

There are 12 octaves that can be defined for 1/1 Octave, and 36 for 1/3 Octave. As you navigate through the list, the screen scrolls down.

SoundAdvisor Model 831C Generating an App Password 9-18

Step 4 At the bottom, choose Select app and choose the app you’re using.

Step 5 Choose Select device, choose Other and give your device a name.

Step 6 Choose Generate.

Step 7 Enter the app Password on the System Properties Email tab. Thepassword is the 16-character code in the yellow bar on your device.

TAKE NOTE Most of the time you’ll only enter the app password once per app or device, so you don’t need to memorize it.

Step 8 If desired, select Generate a Test Email.

SoundAdvisor Model 831C 10-1

Module 1 System InformationSystem information is contained on the About Menu.

On the 831C, go to Tools About to view the following details on 3tabs:

FIGURE 10-1 About

SoundAdvisor Model 831C Locking the Meter 11-1

Module 11 Using the Meter LockTo prevent unauthorized use or tampering with measurements anddata, you can lock the 831C. There are three options of tamper-proofsecurity provided by this feature.

11.1 Locking the Meter ..............................................................................................................11-1

11.2 Choosing a Lock Mode ......................................................................................................11-2

11.3 Allowing Calibration When Locked ..................................................................................11-4

11.4 Constraints ........................................................................................................................11-4

11.5 Unlocking the Meter ..........................................................................................................11-4

11.1 Locking the Meter

Step 1 Navigate to Tools Lock.

FIGURE 11-1 Tools Menu

TAKE NOTE Record your unlock code in a secure place, in order to recall the code when needed. Your code can also be retrieved via G4 LD Utility. Navigate to Maintenance tab and choose Lock/Unlock.

SoundAdvisor Model 831C Choosing a Lock Mode 11-2

Step 2 Choose Lock Mode.

Step 3 Enter an Unlock Code. This code can be 1-4 digits. The first digit shouldnot be a zero. If you set “0123” as your code, the meter will save it as“123”.

Step 4 Select the checkbox in-line with Allow Calibration when Locked.

Step 5 Press Close, then choose Yes to save your changes.

11.2 Choosing a Lock ModeWhen the 831C is unlocked, you can access all features and datadisplays, and change any settings.

Click on a link to learn more about the following lock modes withdifferent degrees of security:

• Lock with Auto Store

• Lock with Manual Store

• Fully Locked

FIGURE 11-2 Lock Mode Menu

Lock with Auto StoreThe display defaults to Big Digit format, and you cannot navigate toother views.

FIGURE 11-3 Locked with Auto/Manual Store

LEARN MORE Refer to Table 11.1 on page 11-4 for constraints on the various lock modes.

SoundAdvisor Model 831C Choosing a Lock Mode 11-3

In Lock with Auto Store mode, a measurement can run, stop, and store,be cannot be paused. When the measurement is stopped, the“Measurement O ” dialog box appears. Select Yes to save themeasurement with an auto-generated file name. Select No to cause areset without saving.

If your System Properties indicate an auto store prompt, you will beprompted to change the file name and save the file. If you select No,the measurement stops and data remains unsaved on the meter.

LEARN MORE To learn more about Big Digit format, see 4.1.2 About the Big Digit Sound Page (Live Tab Page 2)

Lock with Manual StoreThe data view defaults to Big Digit format and you cannot navigate toother views.

A measurement can run, stop, store, and reset in this lock mode.

If you’ve indicated an auto-store mode in your current setup file, themeasurement runs and stores as indicated in the Setup.

Fully LockedA fully locked screen shows only the padlock image. In this lock modeyou can run a measurement, but cannot pause, stop, or reset. You canchoose to fully lock the screen during a measurement.

If you’ve indicated an auto-store mode in your current setup file, themeasurement runs and stores as indicated in the Setup.

FIGURE 11-4 Locked Screen

SoundAdvisor Model 831C Allowing Calibration When Locked 11-4

11.3 Allowing Calibration hen LockedWhile in any of the three lock modes, the 831C can be calibrated, if themeasurement is stopped and the Allow Calibration hen Locked waschecked in the Lock Mode settings dialog.

Press the center softkey to navigate to the Calibrate display. Forinformation on how to calibrate, see “Calibrating Your SoundAdvisor831C” on page 5-1.

11.4 Constraints

The 831C can be accessed, locked/unlocked, settings can be changed,and the measurement can run, pause, stop and store during a lockwhen operated using G4 LD Utility.

11.5 Unlocking the MeterTo unlock the 831C, follow these steps:

Step 1 Press the Tools or 5 ENTER button.

Step 2 Press 5 ENTER again to open the virtual keypad.

Step 3 Enter your Unlock Code, then press 5 ENTER.

FIGURE 11-5 Unlock Code Dialog and irtual eypad

To unlock your 831C via G4 LD Utility follow these steps:

Table 11.1 Allowed Operations During Lock

Lock Mode Run Pause Stop Reset Calibration

Lock with Auto Store Yes No Yes Yes Yes (when stopped)

Lock with Manual Store Yes No Yes Yes Yes (when stopped)

Fully Locked Yes No No No Yes (when stopped)

SoundAdvisor Model 831C Unlocking the Meter 11-5

Step 1 Connect your 831C to G4. See 3.7.1 Operating the 831C from G4 LD Utility.

Step 2 Select your meter in the Meters Panel, then navigate to the Maintenancetab in the Meter Manager.

Step 3 Select Lock/Unlock.

Step 4 From the Lock Mode drop-down, select Unlock. You can also enter theUnlock Code shown in G4 into the Unlock Code dialogue on the meter.

Step 5 Choose Upload.

SoundAdvisor Model 831C Troubleshooting Bad Flash Block Error 12-1

Module 1 System UtilitiesThe System Utilities can repair or recover any file system problems.These functions are similar to what you might use to troubleshoot ahard drive.

To access these features on the 831C, go to Tools System Utilities.

FIGURE 12-1 System Utilities

Format and Restore DefaultsThis function formats the internal data storage in the 831C memory.The meter is then restored to factory settings. Only Meter Preferencesand System Properties are preserved.

CAUTION All data saved on the meter will be lost. This includes calibrations and calibration history. For AudCal users, using Format and Restore also clears the AudCal database.

TAKE NOTE If a measurement is running, stopped, or paused, a Reset is required.

12.1 Troubleshooting ad Flash lock ErrorThe Flash memory device used by the 831C contains a controller thatperforms dynamic bad block mapping. In the event that a flash blockfails after it’s written, you may see a bad flash block error message.

If this occurs, download and save your data from the 831C to a USBdrive or PC, and then select Check File System for either the internal orUSB storage as shown in Figure 1 -1. This feature forces the controllerto re-map all bad blocks.

TAKE NOTE Data in a bad flash block is usually unrecoverable. Check these files for errors if you receive this error message.

1. Checking the file system can help you detect and repair problems.

2. Format the data storage of the area indicated: USB or Internal.

SoundAdvisor Model 831C Connecting to an Ethernet Port 13-1

Module 13 831C Network and Connections In this module:13.1 Connecting to an Ethernet Port ........................................................................................13-1

13.2 Setting Up the Meter’s Network ID ...................................................................................13-1

13.3 Setting a Static IP Address ................................................................................................13-213.3.1 Setting Up Alert Notifications When Using a Static IP Address ........................13-2

13.4 Using WiFi On Your 831C SoundAdvisor ...........................................................................13-313.4.1 Connecting to a WiFi Network ............................................................................13-313.4.2 Using 831C as a WiFi Access Point ......................................................................13-4

13.1 Connecting to an Ethernet PortTo connect the 831C to an Ethernet port, follow these steps:

Step 1 Verify that you have the following equipment:

• SoundAdvisor Model 831C SLM

• DV 012 USB/Ethernet dongle

• Ethernet cable

• A functional Ethernet network port

Step 2 Connect the assembly as shown in Figure 13-1 831C Connected toEthernet.

FIGURE 13-1 831C Connected to Ethernet

13.2 Setting Up the Meter s Network IDYou can access your meter’s networking properties (which includes thenetwork password, IP address, and MAC address) in 2 locations:

Insert the Ethernet adapter (DV 012) into the auxiliary port on the bottom of the 831C.

Connect the Ethernet cable to the Ethernet adapter (DV 012)

Plug in to an Ethernet port in a wall jack or in another supported device.

NOTE: Ethernet connections consume a high amount of power. We recommended that you also connect the meter to an external power source (or by USB) while connected.

SoundAdvisor Model 831C Setting a Static IP Address 13-2

• Tools Communication

• Tools System Properties Network

13.3 Setting a Static IP AddressYour meter will communicate more efficiently with other devices andcomputers when you set a static IP address.

Before you begin:• Connect your meter to G4 via USB. For more information, see

3.7.1 Operating the 831C from G4 LD Utility.

Step 1 On your meter, go to Tools System Properties Network.

Step 2 Enter your IP, Subnet, and Gateway addresses.

Step 3 Select Set Static IP, then reboot the meter for these settings to takeeffect. If you select Disable, the meter uses DHCP to get an IP addressfrom a DHCP server on the local network.

13.3.1 Setting Up Alert Notifications hen Using a Static P Address

Before you begin:• Complete 13.3 Setting a Static IP Address

Step 1 Obtain the IP address of your mail server.

Step 2 On your 831C, go to Tools System Properties Email.

SoundAdvisor Model 831C Using WiFi On Your 831C SoundAdvisor 13-3

Step 3 Enter the email server IP as the Hostname.

Step 4 Complete all other fields on the Email Preferences tab, and click SendTest Email. Contact your local IT support for assistance, if needed.

13.4 Using iFi On Your 831C SoundAd isorIn this section:

• 13.4.1 Connecting to a iFi Network

• 13.4.2 Using 831C as a iFi Access Point

13.4.1 Connecting to a i i Network

To connect the 831C to an existing WiFi network, follow these steps:

Before you begin:

• Connect a WiFi USB adapter to the 831C. The WiFi statusicon appears in the top left.

Step 1 Navigate to Tools Setup iFi.

Step 2 Select an available network. If no network appears on the list, selectMenu and select Refresh List as shown in Figure 1 - .

TRY THIS To connect to a hidden network, click Menu Add Network and provide the network name.

SoundAdvisor Model 831C Using WiFi On Your 831C SoundAdvisor 13-4

Step 3 If required, enter the network password, and click Add.

Step 4 Verify your network connection details by clicking the newly addednetwork in the list.

FIGURE 13-2 iFi Setup

13.4.2 Using 31C as a i i Access Point

Setting the 831C as an Access Point enables the meter to broadcast aWiFi signal that other devices can connect to.

Before you begin:

• Download the LD Atlas app for mobile devices.

• Connect a WiFi USB adapter or USB hub (for multiple devices) tothe 831C. The WiFi status icon appears in the top left.

Step 1 On your 831C, go to Tools Setup iFi.

Step 2 Select Menu.

Step 3 In the menu window that opens, select Set Access Point, and confirmyour choice in the pop-up window. The Access Point icon appears in

the top left.

Step 4 On another device, choose the 831C as the WiFi network, and enter thepassword: wifi831c.

Step 5 On your mobile device, open the LD Atlas app, and select the name ofyour meter.

LEARN MORE The LD Atlas app is available for iOS and Android devices. For more information, see 3.7.2 Operating the 831C from the LD Atlas App.

The signal strength indicator and secure network icon (Network requires a password if secure).

Press the Refresh button if there are no available networks.

SoundAdvisor Model 831C Updating the G4 LD Utility 14-1

Module 1 Upgrading Firmware & OptionsIn addition to meter operation, the G4 LD Utility (G4) is also used toinstall firmware and option upgrades as shown in the followingprocesses.

In this module:14.1 Updating the G4 LD Utility ................................................................................................14-1

14.2 Upgrading 831C Firmware by Using G4 LD Utility ............................................................14-1

14.3 Upgrading Options ............................................................................................................14-2

14.4 Enabling or Disabling Optional Firmware ........................................................................14-3

14.1 Updating the G4 LD Utility

Step 1 Locate the G4 installer on the LD USB Drive included with your meter, orfrom www.LarsonDavis.com/G4.

Step 2 Double-click to download the G4 installer.

Step 3 Once the file is downloaded, unzip or extract the folder to your Desktop.

Step 4 Open the new folder and run setup.exe.

Step 5 Follow the on screen instructions to install the upgrade.

Step 6 To launch G4, use the shortcut the installer created on yourDesktop, or select G4 from the Start Menu.

14.2 Upgrading 831C Firmware by Using G4 LD UtilityBefore you begin:

• Power on your meter, and connect it to your PC via the USBcable (CBL138, part of the PSA029 power supply) or via TCP/IP.For more information about connecting your meter, see Module13 831C Network and Connections.

Step 1 In the G4 Meters Panel, your connected meter displays in blue with one ofthe following connection type indicators:

Connection Types:

TCP/IP via Local Area Network (LAN)

TCP/IP via Internet

USB

WiFi

SoundAdvisor Model 831C Upgrading Options 14-2

Step 2 Click the more options icon in-line with your meter, and selectUpgrade Firmware from the pop-up menu. This opens the UpgradeFirmware or Options window.

Step 3 Click Choose Firmware File. This opens the File Explorer to the defaultfirmware folder. G4 ships with the latest 831C firmware in this location.

Step 4 Select the F 831C file you want to install, and click Open.

Step 5 Confirm your choice by clicking Upload Firmware. A progress barappears under the Upload Firmware button followed by progressscreens until the firmware is upgraded.

14.3 Upgrading OptionsBefore you begin:

• When you purchase an upgrade or option, you will receive thefirmware upgrade file (in OP831C format) as an emailattachment from Larson Davis. Save this file to your PC on theDesktop.

• Power on your meter, and connect it to your PC via the USBcable (CBL138, part of the PSA029 power supply) or via TCP/IP.For more information about connecting your meter, see Module13 831C Network and Connections.

Step 1 In the G4 Meters Panel, your connected meter displays in blue with one ofthe following connection indicators:

from the pop-up menu. This opens the Upgrade

Connection Types:

TCP/IP via Local Area Network (LAN)

TCP/IP via Internet

USB

WiFi

SoundAdvisor Model 831C Enabling or Disabling Optional Firmware 14-3

Step 2 Click the more options icon in-line with the name of your meter, andselect Upload Options from the pop-up menu. This opens the UpgradeFirmware or Options window.

Step 3 Click Choose Options File. This opens the File Explorer to the defaultfirmware folder.

Step 4 Navigate to the Desktop (or to the location of the OP831C file you receivedin the option upgrade email from Larson Davis), select the file you wantto install, and click Open.

Step 5 Confirm your choice by clicking Upload Options. A progress bar underthe Upload Options button shows the status of your update and aseries of progress screens.

Step 6 To confirm the installation, do the following: on your 831C, navigate toTools About Options to view your currently installed options.

LEARN MORE For details about customizing your firmware options, see 14.4 Enabling or Disabling Optional Firmware.

14.4 Enabling or Disabling Optional FirmwareOnce you download and install optional firmware, it’s automaticallyenabled on your meter. To disable a firmware option, complete thesteps in this section.

Step 1 On your 831C, navigate to Tools System Properties.

Step 2 Press the top-left or top-right softkey (*/*)until you see the Optionsscreen.

Step 3 Select the checkbox in-line with the option you want to enable or disableon the meter.

TAKE NOTE If you have unsaved data or are currently running a measurement, the meter notifies you that a reset is needed to save the Options settings. Select OK and press the Reset 1 button to reset the measurement.

Step 4 Reboot your 831C.

TAKE NOTE If desired, you can temporarily hide the display tab (screen) of a disabled option. For more information, see 4.5 Enabling or Disabling Display Tabs.

SoundAdvisor Model 831C Setting Up a Measurement With Measurement History 15-1

Module 15 Using Measurement HistoryThis module shows how to use the Measurement History feature offirmware option 831C-ELA, which allows you to segment the datagathered between Run and Stop into measurement intervals. YouMeasurement intervals can be saved as multiple records in a singledata file.

Option 831C-ELA provides exceedance-based logging analysis withmanual or timed storage of statistical data and measurement history.

In this module:15.1 Setting Up a Measurement With Measurement History .........................15-1

15.2 Viewing Measurement History Data Files ................................................ 15-6

15.1 Setting Up a Measurement With Measurement History Using Measurement History, the meter automatically creates a series ofmeasurement intervals based on the time you define. Whilemeasurement parameters can be indicated directly in the Active setup,it’s a good practice to save a setup file for each specific measurementyou perform as shown in this section.

TAKE NOTE The G4 LD Utility also provides a simple, file transfer-style interface for configuring, saving, and transferring setup files to your PC or to another meter. For more information, refer to the G4 LD Utility Manual.

Before you begin:• Verify that firmware option 831C-ELA is installed and enabled

on your meter. For more information, see 14.4 Enabling orDisabling Optional Firmware.

• Create a measurement setup file (Setup) as shown in 6.2Creating a Custom Setup File.

Step 1 Go to Tools 3 Setup Manager or Menu Setup Manager.

Step 2 Highlight the name of the Setup file you want to configure withMeasurement History.

Step 3 Press the top-right softkey (//*) until the Control tab appears.

Step 4 Select a Run Mode and associated settings to complete the Setup. Click alink below for instruction on completing the Setup:

• Selecting Manual or Stop When Stable Mode WithMeasurement History


• Selecting Single Block Timer Mode With MeasurementHistory

• Selecting Continuous Mode With Measurement History

• Selecting Single Block Timer Mode With MeasurementHistory

• Selecting Daily Timer Mode With Measurement History

Selecting Manual or Stop When Stable Mode With Measurement History

a. Select the Enable Measurement History checkbox.

b. If you want to send a measurement interval exceedance alert,select your preferred method in-line with Alerts, then select aTrigger Source and Trigger Level (dB) for the alert. The TriggerLevel cannot be less than 0.1 (dB).

TAKE NOTE Trigger Sources for this alert include the following statistics: LAeq, LCeq, LZeq, Lmax, Lmin, and all 6 values of Ln. If the current dB level is greater than the Trigger Level (dB) of the selected Trigger Source at any time during the current measurement interval, the 831C sends an alert notification via email or text when the interval ends.

c. Select any additional settings on the Setup Manager tabs. Formore information on this process, see 6.2.2 Customizing SetupValues On the Setup Manager Tabs.

d. Press Close (/*/) and save your Setup.

e. Set it as the Active setup file.

f. Go to System Properties Preferences and verify the Auto-Store setting. With Measurement History enabled in ManualRun/Stop or Stop When Stable mode, the meter will store dataafter the measurement according to this setting. For moreinformation, see 8.1 Setting Data File Storage Preferences.

g. Make a measurement.

TRY THIS With Measurement History enabled, sequentially pressing the STOP/STORE and RUN/PAUSE buttons stores the measurement and initiates another measurement. This eliminates the need to perform a separate store.

Selecting Timed Stop Mode With Measurement History

When Measurement History is enabled, Timed Stop allows you toautomatically make and store the number of measurements you set asthe Measurement Counter and then stop. Subsequent runs, each

LEARN MORE To view suggested applications for each run mode, see 6.2.3 Choosing a Run Mode.


manually initiated, produce the same number of storedmeasurements.

a. In the Time (hh:mm:ss) field, enter a length of time for themeasurement.

b. Select the Enable Measurement History checkbox, and enterthe number of measurement records you want in theMeasurement Counter field.

TAKE NOTE To use the Measurement Counter, the value of Time must be greater than 00:01:00 (1 min).

FIGURE 15-1 Timed Stop Mode

c. If you want to send a measurement interval exceedance alert,select a checkbox in-line with Alerts.

d. Select a Trigger Source and Trigger Level (dB) for the alert.The Trigger Level cannot be less than 0.1 (dB).

TAKE NOTE Trigger Sources for this alert include the following statistics: LAe , LCe , L e , Lmax, Lmin, and all 6 values of Ln. If the current dB level is greater than the Trigger Level (dB) of the selected Trigger Source at any time during the current measurement interval, the 831C sends an alert notification via email or text when the interval ends.

e. Select any additional settings on the Setup Manager tabs. Formore information, see 6.2.2 Customizing Setup Values On theSetup Manager Tabs.

f. Press Close (/*/) and save your Setup.

g. Set it as the Active setup file.

h. Go to System Properties Preferences and verify the Auto-Store setting. In Timed Stop mode, the meter will store data

The measurement setup shown here makes 1 measurement history record that last 20 seconds.

93


after the measurement according to this setting. For moreinformation, see 8.1 Setting Data File Storage Preferences.

i. Make a measurement.

Selecting Continuous Mode With Measurement History

a. Select a Daily Auto-Store interval. At the end of the Auto-Storeinterval, the 831C saves the measurement record to a new,incrementally-named, data file throughout the day based on theTime (hh:mm:ss). Time is the time of day you want to beginauto-storing measurement records.

TRY THIS If you want to store a measurement record each hour of the day beginning at 10:05, choose the following settings:

• Auto-Store: 1 hr• Time (hh:mm:ss): 10:05:00

If you start the measurement at 10:10, the measurement record storesat 11:05, 12:05, and so forth. In this case, the initial measurementhistory record has only 50 minutes of data, while all others contain thefull hour.

b. If desired, select Cal. Check, and enter the Time of day itshould occur.

c. Select the Enable Measurement History checkbox, and enter aduration (hh:mm) for each measurement record in the IntervalTime field. Note: Interval Time cannot be less than 00:01 (1minute).

d. If desired, select Interval Time Sync. This forces a newmeasurement record to begin every n minutes (or hours), wheren is the value of Interval Time.

• If you enter an Interval Time (hh:mm) value less than0:01, the measurement interval syncs to the 1 min inter-val boundary.

• If you enter any other Interval Time (hh:mm) value of01:00 or more, the measurement syncs to the hour.

e. If you want to send a measurement interval exceedance alert,select a checkbox in-line with Alerts.


f. Select a Trigger Source and Trigger Level (dB) for the alert.


g. Select any additional settings on the Setup Manager tabs. Formore information, see 6.2.2 Customizing Setup Values On theSetup Manager Tabs.

h. Press Close (/*/) and save your Setup.

i. Set it as the Active setup file.

Selecting Single Block Timer Mode ith Measurement History


b. Select the Enable Measurement History checkbox.

c. If you want to send a measurement interval exceedance alert,select your preferred method in-line with Alerts, and select aTrigger Source and Trigger Level (dB) for the alert. The TriggerLevel cannot be less than 0.1 (dB).


Alerts also require the setup process shown in 9.10 Setting Up Alert Notifications (Tools System Properties Email tab).

Trigger Level cannot be 0.1 (dB)

SoundAdvisor Model 831C Viewing Measurement History Data Files 15-6

d. Select any additional settings on the Setup Manager tabs. Formore information, see 6.2.2 Customizing Setup Values On theSetup Manager Tabs.

e. Press Close (/*/) and save your Setup.

f. Set it as the Active setup file.

Selecting Daily Timer Mode With Measurement History


b. If desired, select the checkbox in-line with 2, and 3 to enteradditional measurement periods.

c. Select the Enable Measurement History checkbox.

d. If you want to send a measurement interval exceedance alert,select your preferred method in-line with Alerts, and select aTrigger Source and Trigger Level (dB) for the alert. The TriggerLevel cannot be less than 0.1 (dB).

TAKE NOTE Trigger Sources for this alert include the following statistics: LAeq, LCeq, LZeq, Lmax, Lmin, and all 6 values of Ln. If the current dB level is greater than the Trigger Level (dB) of the selected Trigger Source at any time during the current measurement interval, the 831C sends an alert notification via email or text when the interval ends.

e. Select any additional settings on the Setup Manager tabs. Formore information, see 6.2.2 Customizing Setup Values On theSetup Manager Tabs.

f. Press Close (/*/) and save your Setup.

g. Set it as the Active setup file.

Recommended Next Steps

• Make a measurement. For more information, see ModuleModule 7 Making a Measurement.

• View and interpret the resulting data. For more information, see15.2 Viewing Measurement History Data Files.

15.2 Viewing Measurement History Data FilesIn this section:

• 15.2.1 Viewing Live Measurement Interval Data

• 15.2.2 Viewing Measurement History Data

• 15.2.3 Viewing Measurement History Data From a Stored File


15.2.1 Viewing Live Measurement nterval Data

When the first measurement interval is underway, metrics and datadisplay on the Current tab. When the measurement interval iscomplete, that data displays on the Measurement tab. The Current tabresets and begins displaying data for the next measurement interval inprogress. At any time the Current tab displays the measurementinterval currently in progress.

The Current tab displays data in pages just like Live or Overall, anddepending on the firmware options Setup values enabled. Press the UPand DOWN directional buttons ( and ) to navigate throughthese pages. For more information, see Module Module 4 Using theData Display.

15.2.2 Viewing Measurement History Data

The Measurement tab can display data for any of the previouslycompleted measurement intervals. Intervals (records) are numberedsequentially first to last and displayed left to right.

FIGURE 15-2 Measurement History

Changing the Displayed Record

The selected record number for which data is being displayed isindicated in the upper right next to the measurement name as younavigate up and down through the pages.

Fre uency Spectra Displays• When a frequency spectrum is displayed, use the RIGHT and

LEFT navigation buttons ( and ) to highlight a frequencyband and display the associated levels.

Selected record number/Number of measurements

Measurement duration

Data and time measurement started

Graph of Leq values for each record (interval), in sequence by time

Leq and max values of the current measurement interval (cursor position) Interval or Record #


• To change the displayed record, shift to a non-spectrum page,then return to the frequency spectrum display.

Non-Spectra DisplaysOn screens that do not contain frequency spectrum displays, use theRIGHT and LEFT navigation buttons (4 and 6) to step right and leftthrough the selected measurement record numbers.

15.2.3 Viewing Measurement History Data From a Stored File

TAKE NOTE We recommend using the G4 LD Utility for viewing data files on your PC. For more information, see the G4 LD Utility Manual.

SoundAdvisor Model 831C Setting up a Measurement With Time History 16-1

Module 16 Using Time HistoryTime History provides a table of metrics recorded at regular intervalsaccording to the settings you choose. This feature is active on yourinstrument when you purchase and enable firmware option 831C-LOG.

16.1 Setting up a Measurement With Time History .................................................................16-116.1.1 Time History Available Metrics ...........................................................................16-2

16.2 Making a Time History Measurement With Sound Markers ............................................16-4

16.3 Viewing Time History Data ................................................................................................16-5

16.1 Setting up a Measurement With Time HistoryTime History describes the measured sound as a table of metricsrecorded at regular intervals.

Before you begin:• Verify that firmware option 831C-LOG is installed and enabled

on your meter. For more information, see 14.4 Enabling orDisabling Optional Firmware.

• Create a measurement setup file (Setup) as shown in 6.2Creating a Custom Setup File.

Step 1 Navigate to Tools 3 Setup Manager.

TAKE NOTE The G4 LD Utility also provides a simple, file transfer-style interface for configuring, saving, and transferring Setup files to your PC or to another meter. For more information, refer to the G4 LD Utility Manual.


Step 2 Highlight the name of the Setup you want to configure with Time History,and press the top right softkey (//*)until the Time History tabdisplays.

Step 3 Check Enable Time History and select the desired time Period from thedrop-down menu.

Step 4 Enable the desired Time History Options. Not all options are available forevery time period. For a complete list of options, see Table 16.1.

Step 5 Select any additional settings on the Setup Manager tabs. For moreinformation on this process, see 6.2.2 Customizing Setup Values Onthe Setup Manager Tabs.

Step 6 Press Close (/*/) and save your Setup.

Step 7 Set it as the Active setup file.

Step 8 Make a measurement as shown in 16.2 Making a Time HistoryMeasurement ith Sound Markers.

16.1.1 Time History Available Metrics

a le 1 1 shows data that is displayed for each Time History Metric,depending on the Time Interval Option you select.


Table 16.1 Time History Available Metrics

Time History Metrics Time Interval Options2.5, 5, 10 ms 20 & 50ms 100 & 200 ms 500 ms, 1 s, 2 s 5 s -24 h

Lωeq l l l l

Lωpeak l l l l

LωSMax l l l

LωFmax l l l

LωImax l l l

LωSmin l l l

LωFmin l l l

LωImin l l l

LωSSPL l l l l

LωFSPL l l l l

LωISPL l l l l

LCeq-LAeq l l l

LIeq-Leq l l l l

OBA BandwidthLeq 1/1 l* l* l l l

1/3 l* l* l l l

Lmax 1/1 l l l1/3 l l l

Lmin 1/1 l l l1/3 l l l

SPL 1/1 l l l l1/3 l l l l

LAFTM5 l

MiscellaneousLn Statistics l l

Battery Voltage l l l

Internal Temperature l l l

External Power l l l

Millisecond Time ResolutionTms l l l l l

Weather** l l l l l* Only 1/1 Octave or 1/3 Octave can be chosen, not both.** 1 second resolution and will not update between queries at faster than 1 second.ω is the weighting A, C, or Z

SoundAdvisor Model 831C Making a Time History Measurement With Sound Markers 16-4

16.2 Making a Time History Measurement ith Sound MarkersThe 831C Time History option also allows you to place sound typemarkers in the time history data as the sounds occur or during yourpost measurement analysis.

To make a measurement with sound markers, follow these steps:

Before you begin:• Complete steps 1–4 of 16.1 Setting up a Measurement ith

Time History.

Step 1 With your Time History setup file highlighted in the Setup Manager, pressthe top softkey (//*) until the Markers tab appears.

FIGURE 16-1 Setup Manager Markers Tab

Step 2 If desired, edit the marker names.

Step 3 Select the checkbox in-line with markers you want to use for thismeasurement.

TAKE NOTE If you’re also planning to make sound recordings, section 18.1 Setting Up Markers for Sound Recording is a good reference.

SoundAdvisor Model 831C Viewing Time History Data 16-5

Step 4 Press Close (/*/)and save the Setup.

Step 5 Enter the Setup Manager, highlight the name of the Time History setup,and set it as the Active setup file.

Step 6 Run a measurement and navigate to the Time History or Live tab.

Step 7 Press the Menu softkey(/*/) and select Mark Sound Type.

Step 8 As shown in Figure 1 - , a partial menu appears over the bottom half ofyour Time History tab. As sound types occur, select any of the availablemarkers to mark that sound type. Deselect the marker to end the mark.

FIGURE 16-2 Marking a Sound Type

16.3 iewing Time History DataTime History data displays on the Time History tab as shown in Figure1 - .

FIGURE 16-3 Time History Tab (Page 1)

Select Motorcycle to mark the beginning of the sound. Deselect it to mark the end.

Highlight this line and use the 5 key to toggle from Record view to the metric view.

Blue bands show the LAeq for the time interval. Green marks the metric data (LAPeak is shown here).

Depending on the enabled firmware options and the measurement setup used, the Time History screen can display data pages just like Live or Overall. Press the UP

and DOWN navigation buttons to navigate through these different pages. See Figure 1 -4.

To jump to a different record number, press the Menu softkey and select Locate from the pop-up menu.

SoundAdvisor Model 831C Viewing Time History Data 16-6

Time History Octave Spectra PagesIf you indicated OBA metrics, the Time History tab contains multiplepages of Octave Spectra data as shown in Figure 1 -4.

TRY THIS Use the 5 button on each visible Time History page to test which values you can change on each page.

FIGURE 16-4 Time History 1/1 Octave Page

The highlighted band is the Lωeq average sound level of for the duration of the measurement at that frequency.

Use the LEFT and RIGHT navigation buttons to highlight the desired band the numerical values below reflect the information at that octave.

Use the ENTER 5 button to jump your cursor from frequency or record number.

LEARN MORE To learn more about octave page displays, see Module 4 Using the Data Display.

The selected record number of the highlighted data.

SoundAdvisor Model 831C Setting Up the Event History Measurement 17-1

Module 1 Using Event HistoryThis module shows how to perform a measurement using EventHistory, a feature of option 831C-ELA. Option 831C-ELA provides event-based logging analysis and event history data with manual or timedstorage of statistical data and measurement history.

As shown in Figure 17-1, an event occurs when the measured soundpressure level exceeds at least one Trigger Level and persists (longerthan the Minimum Duration you define).

FIGURE 17-1 Sound Event

In this Module:17.1 Setting Up the Event History Measurement .....................................................................17-1

17.2 Storing Event Data ............................................................................................................17-417.2.1 Using (Continuous) Daily Auto-Store With Event History .................................17-5

17.3 Viewing Event History Data on the Event History Tab .....................................................17-517.3.1 Event History Spectral Display ...........................................................................17-6

17.4 Understanding Triggering Methods .................................................................................17-717.4.1 Understanding Level Triggering .........................................................................17-817.4.2 Understanding Dynamic Triggering ...................................................................17-8

17.1 Setting Up the E ent History MeasurementThis section shows how to add some or all of the following capabilitiesto a measurement setup file: Trigger Levels, Event History, Event TimeHistory, and Alert Notifications.

Before you begin:• Verify that firmware option 831C-ELA has been installed and

enabled on your meter. For more information, see 14.4Enabling or Disabling Optional Firmware.

Step 1 Navigate to Tools Setup Manager.

As shown by the Event Stop, an event ends when the sound level drops 2 dB below the trigger level. This 2 dB hysteresis is to avoid the creation of multiple exceedances when the sound level is fluctuating at or near the trigger level.


TAKE NOTE The G4 LD Utility also provides a simple, file transfer-style interface for configuring, saving, and transferring Setup files to your PC or to another meter. For more information, refer to the G4 LD Utility Manual.

Step 2 Highlight the name of the Setup you want to configure with Event History.

TAKE NOTE If you’re using Continuous Run Mode with Event History, see Table 17.1 to predict how events will be logged when they persist from one Auto-Store Period into the next.

Step 3 Press the top-left softkey (*//) until the Event Triggers tab displays.

Step 4 If needed, edit the Trigger Source, and Trigger Level values.

Using Running Le as a Trigger Source

Using this setting, if the Leq for the most recent period is greater thanthe set Trigger Level, the meter creates an event.

a. Select Running Le from one of the Trigger Source drop-downs, and enter a Trigger Level in dB.

b. Use the top softkeys (*/*) to navigate to the SLM Tab of theSetup Manager.

c. Enter a Running Le period in seconds. Enter whole numbers1–3600 (1 hour).

FIGURE 17-2 Setup Manager: SLM Tab

Step 5 Press the top-left softkey (*//) to navigate to the Event History tab.

Step 6 Select the checkbox in-line with Event History, and enter values for theMin/Cont Duration.

About the Minimum Duration: To prevent many small events of shortduration, you can select a Minimum Duration. This is the length of

In this example, the period is the Leq of the last 1200 seconds of the measurement run time.


time in seconds that levels must exceed the threshold SPL and Peaklevels to be labeled an event. This value can be 60 seconds or less.

TAKE NOTE If you are using this feature with Sound Recording, there are constraints on your Minimum Duration. See 18.3.1 About Sound Recording Constraints.

About the Continuation Period: A noise event is initiated when thesound level exceeds the threshold level for SPL1 or Peak 1. There maybe situations where the sound level drops below the threshold level fora short period before exceeding them again. Statistically, if you want toconsider this a continuation of the first event rather than a new event,you can set a Continuation Period. This is the length of time inseconds following an event where the measured sound level can dipbelow, then exceed the threshold level again, and still be statisticallyconsidered part of the initial event. This value must be 9 seconds orless.

However, if the measured level drops below the threshold level andremains below it during the continuation period, the noise event isconsidered complete.

Step 7 Select Level or Dynamic from the Trigger Method drop-down.

LEARN MORE For more information, see 17.4 Understanding Triggering Methods.

Step 8 If you want to send or receive alert notifications for sound events, selectyour preferred method (or both) in-line with Alerts.

LEARN MORE Alert notifications also require configuring the network preferences on the meter as shown in 9.10.1 Enabling Alert Notifications for Sound Events.

Step 9 If desired, enable Event Time History, and choose values for thefollowing optional settings:

FIGURE 17-3 Event Time History

• Period

Event Time History feature provides regularly logged metrics over theduration of a sound event according to the period you specify here.

• Spectral Mode

Duration of each time history sample during the course of an event.

SoundAdvisor Model 831C Storing Event Data 17-4

Enabling Spectral Mode collects frequency bandwidth information forthe duration of the sound event. To locate this information in the datafile, see 17.3.1 Event History Spectral Display.

• Pre/Post Event

Pre-Trigger and Post-trigger values indicate the number of samples youwant to log prior to the event and after the event, respectively. Asample is equal to the Event Time History Period.

• Event Samples

The Event Samples value indicates the maximum number of samplesyou want to record for each event. Choose any value 10–9999. Once themaximum is reached, no samples are logged, even if the eventcontinues or post-trigger samples were set.

Example: If the sample Period is 1 second, the event lasts 15 seconds,and Event Samples is 10, only the first 10 periods (seconds) will belogged. Since this event extends beyond the maximum sample time,there will be no post-trigger sample logged, regardless of the set PostEvent value.

Step 10 Press Close (/*/)and save the Setup.

Step 11 Enter the Setup Manager, highlight the name of the Event History setup,and set it as the Active setup file.

Step 12 Run an Event History measurement.

Recommended Next Steps• Store a data file as shown in 17.2 Storing Event Data.

• View resulting data as shown in 17.3 Viewing Event HistoryData on the Event History Tab.

17.2 Storing Event DataEvent history data can be displayed during a measurement and after ithas been stopped. However, how and when measurement data isstored in a data file depends on the meter Auto-Store preference, orthe Run Mode selected in the measurement setup file. If you haven’tconfigured these settings to auto store, the data has not been stored tomemory. To manually store a data file after a measurement is stopped,press the 7 (STOP/STORE) button.

SoundAdvisor Model 831C Viewing Event History Data on the Event History Tab 17-5

17.2.1 Using (Continuous) Daily Auto-Store With Event History

When using the Daily Auto Store feature of the Continuous Run Mode,longer events can affect the auto-store period in the following ways:

When using 5-, 2-, or 1-minute Daily Auto-Store settings, the 831Cstrictly observes the Time and Auto-Store period you select to fulfill theevent logging function.

For example, when a sound event persists across an Auto-Storeboundary, the 831C will store and begin a new data file, which willcontain the remainder of the event data.

However, when a sound event persists across the Auto Store boundarywhen using longer Daily Auto-Store periods (10 min+), the 831C waitsup to 1 minute to allow an in-progress event to end before storing thefile.

17.3 Viewing Event History Data on the Event History TabFrom the Live Tab, press the top-right softkey (/*/) until the Eventstab displays. After the first time interval has passed, data displays onthe Event History tab in single values.

The Events tab can display multiple data pages just like the Live orOverall screens, depending on the firmware options enabled and thesetup used. Use the 8 and 2 buttons to navigate through differentpages on the Event History Tab. For more information, see 2.3.2 UsingTabs and Pages.

Table 17.1 How Longer Events Can Affect the Auto Store Period

Daily Auto-Store Value Mid-Event Auto-Store Result

5 min, 2 min, or 1 min Stores strictly according to the Period selected

10 mins and longer Waits for event to end (up to 1 min) before storing

SoundAdvisor Model 831C Viewing Event History Data on the Event History Tab 17-6

FIGURE 17-4 Event History Tab

FIGURE 17-5 Event Indicator

1 .3.1 Event History Spectral Display

If you enabled Spectral Mode in the measurement setup, the EventHistory tab will display multiple pages of data as shown in Figure 17-4.

TRY THIS Press the 5 button on each Event History page to edit certain values on each page.

LEARN MORE To learn more about octave page displays, see the following sections:

• 4.1.3 About the Octave Band Analyzer Page (Live Page 3)

• 4.1.4 About the Normalized Octave Band Page (Live Page 4)

Selected event number/number of measurementsGreen line represents the

Trigger Level

Event Indicator See Figure 17- .

The 3 events are 3 instances in which the noise level exceeded the Trigger Level for the Minimum Duration as indicated in the Setup.

ReadyAll the pre-samples are recorded and it is waiting for an event

TriggerThe sound level exceeds the Trigger Level.

ValidThe sound level exceeds the Trigger Level for the Minimum Duration.

ContinueThe sound level is below the Trigger Level and is in the Continuation Period until the event continues or the event ends.

SoundAdvisor Model 831C Understanding Triggering Methods 17-7

FIGURE 17-6 Event History Tab 1/3 Octave Page

FIGURE 17-7 Changing Record Number

Navigating Events in Octave Displays

Use the and navigation buttons to move from event to event to theright or left, respectively.

To change the octave view, press ENTER 5 to jump your cursor fromthe record number to the frequency, then press the or navigationbuttons to highlight different frequencies. Numerical values reflect theselected frequency.

17.4 Understanding Triggering MethodsIn this section:

• 17.4.1 Understanding Level Triggering

• 17.4.2 Understanding Dynamic Triggering

Your 831C SLM provides 2 ways to calculate an event trigger. The eventtrigger using Level Triggering is the static value you set. With dynamictriggering, the event trigger level adjusts according to the backgroundnoise (and any indicated offset) in each time history period.

The highlighted band is the Lωeq average sound level for the duration of the event at that frequency.

Use the and buttons to highlight the desired band. The numerical values below display values for that octave.

Use 5 to highlight the frequency, OBA value, or the reference.

To learn more about octave page displays, see 4.1.4 About the Normalized Octave Band Page (Live Page 4).

To jump to a different record number, press the Menu softkey (/*/) and select Locate from the pop-up menu.


1 .4.1 Understanding Level Triggering

Using this method, all triggers are determined directly by their setthreshold level, which is static throughout the entire measurement.The threshold level is calculated using all measured sound.

FIGURE 17-8 Event History with Level Triggering

FIGURE 17-9 Event History with Level Triggering and Events

1 .4.2 Understanding Dynamic Triggering

With dynamic triggering, the 831C tracks the background noise level,and adjusts the Trigger Level to equal the background noise plus anyindicated offset. This effectively removes background noise from thetrigger level calculation. To calculate events based on event noise only,Dynamic triggering is an appropriate method.

The Leq in this example ran for a 24 hour period using a 1 second Time History Period. The event trigger level was set at 84dB.

The bars represent events logged during the measurement. At a minimum of 3 seconds, there are about 5.


FIGURE 17-10 Event History with Dynamic Triggering

FIGURE 17-11 Event History with Dynamic Triggering and Events

About the Background LevelThe background sound level used with dynamic triggering is the user-indicated Ln level (Setup Manager Ln Tab), calculated using an

0

10

20

30

40

50

60

70

80

90

100

0:00:00 1:56:39 3:53:19 5:49:59 7:46:39 9:48:18 11:44:58 13:41:38 15:38:18 17:34:58 19:31:38 21:28:18 23:24:58

Leq Background tracking level Dynamic Trigger Level

The Leq is set the same as in Figure 17-8 Event History with Level Triggering.

The background level is tracked throughout the measurement.

The trigger level is adjusted based on the background level and an indicated offset. Here the offset is 20 dB.

0

10

20

30

40

50

60

70

80

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0:00:00 1:56:39 3:53:19 5:49:59 7:46:39 9:48:18 11:44:58 13:41:38 15:38:18 17:34:58 19:31:38 21:28:18 23:24:58

Leq Background tracking level Dynamic Event Dynamic Trigger Level

With dynamic triggering, the exceedances only occur if the level exceeds the background level plus the offset. Here the offset is 20 dB.

The bars represent events logged during the measurement. There are about 11 with a Minimum Duration of 3 seconds.


algorithm which includes the rise rate in dB per minute. There are 5Dynamic Trigger Parameters options available:

When the measurement first begins, the background tracking level isset to the following:

Trigger Level SPL 1 – Offset = Initial Background Level

As the sound level increases above the background tracking level, thetracking level will increase at the rise rate. As the sound decreasesbelow the tracking level, the tracking level will decrease at the ratedetermined by the dynamic response (Ln Percentile and its rate).

Thus, the dynamic trigger level is set to the following:

Background level + Offset = Trigger Level

Table 17.2 Dynamic Response

Setting Number Tracking Ln Percentile

Rise Rate, dB/minute Description

1 95% 1/2 Lower tracking level

2 90% 1/3 Slow

3 90% 1/2 Default, normal operation

4 90% 1 Fast

5 80% 1 Fast and higher tracking level

SoundAdvisor Model 831C Setting Up Markers for Sound Recording 18-1

Module 18 Using 831C Sound RecordingThis module demonstrates the features and settings of the 831Csound recording firmware option 831C-SR. Recording event sounds isoften used to help identify the source of loud noise.

This feature allows you to trigger a recording and add a sound typelabel to the resulting measurement data in 3 ways: by creating amanual sound recording, by setting automated event-triggeredrecording, and by using measurement history event recording.

In this module:18.1 Setting Up Markers for Sound Recording .........................................................................18-1

18.2 Making a Manual Sound Recording Using Mark Sound Type ..........................................18-2

18.3 Making an Automated Event Sound Recording ...............................................................18-318.3.1 About Sound Recording Constraints .................................................................18-4

18.4 Enabling Measurement History Sound Recording ...........................................................18-5

18.5 Understanding Recording Settings and Sound Quality ..................................................18-618.5.1 Understanding Resolution, Peak Overload .......................................................18-618.5.2 Selecting an Appropriate Sound Recording Range ...........................................18-718.5.3 Choosing a File Format for Sound Records .......................................................18-7

18.6 Sound Recording Playback ...............................................................................................18-818.6.1 Playback on the 831C .........................................................................................18-818.6.2 Playback After Saving in G4 ................................................................................18-8

18.1 Setting Up Markers for Sound RecordingMarkers help you label and initiate a recording of the sound beingmeasured. You can also use markers to simply mark the soundoccurrence with a label that’s saved in the measurement’s TimeHistory.

Before you begin:• Verify that 831C-SR firmware is installed and enabled on your

meter. For more information, see 14.4 Enabling or DisablingOptional Firmware.

Step 1 On the meter, go to Tools Setup Manager.

Step 2 Highlight the setup file you want to enable for Sound Recording, thenpress the top-left softkey (*//) until you see the Markers tab.

SoundAdvisor Model 831C Making a Manual Sound Recording Using Mark Sound Type 18-2

Step 3 Select the checkbox in-line with 1 or more sound types to enable soundrecording for that type.

FIGURE 18-1 Setup Manager Markers

Step 4 When your sound settings are complete, press the Close softkey (/*/),and save the Setup.

Step 5 Next, set your setup file as the Active Setup.

Step 6 Press the Close softkey(/*/), and save your Setup. If you select Cancel,you return to the Setup Manager without saving.

Step 7 Run a measurement and manually mark the sound types as shown in18.2 Making a Manual Sound Recording Using Mark Sound Type.

18.2 Making a Manual Sound Recording Using Mark Sound TypeDuring a measurement, you can manually record any sound the meteris currently measuring.

Before you begin:• Complete the process shown in 18.1 Setting Up Markers for

Sound Recording.

Step 1 With a measurement currently running, use the left or right softkeys(*/*) to navigate to the Live tab.

To enter or edit a sound type name, highlight the name field and press e.

SoundAdvisor Model 831C Making an Automated Event Sound Recording 18-3

Step 2 Press Menu (/*/) and select Mark Sound Type. As shown in Figure 1 -the bottom half of the screen displays a list of all enabled markers(sound types).

FIGURE 18-2 Mark Sound Type Sound Recording

Step 3 Select the checkbox in-line with a marker to start the recording. Whenfinished, a labeled sound record displays in the data file.

TAKE NOTE You can also press the left softkey (*//)to initiate a sound recording. To stop recording using this method, select Stop, Close, or stop the measurement. If you don’t manually stop the sound recording, it will stop when the memory is full. Very large data files are time consuming to download and playback.

18.3 Making an Automated E ent Sound RecordingBefore you begin:

• Open the Setup Manager (Tools Setup Manager) and create asetup file with Event History enabled as shown in 17.1 SettingUp the Event History Measurement.

Step 1 On your meter, go to Tools Setup Manager. Highlight your setup file,then press the top-left softkey (*//) to open the Sound tab.

Step 2 Select the checkbox in-line with Save Event Sound, and enter any otherapplicable values.

FIGURE 18-3 Sound Event Settings

TAKE NOTE If Event History is not enabled, but Event Sound is, the 831C will still make a sound recording for an event.

When you select a marker with sound recording enabled, it initiates the Pre-trigger period followed by the sound recording.

Pre-trigger Time is the period prior to the event-based trigger that you want to include in the recording.

Snapshot Time is the time set to record after the event.

For more information, see 18.5.3 Choosing a File Format for Sound Records.

SoundAdvisor Model 831C Making an Automated Event Sound Recording 18-4

Step 3 Save the Setup, set it as the Active setup file, and Close (/*/) the SetupManager.

Step 4 Run a measurement and examine the resulting sound recordings. Basedon the settings shown in Figure 1 - , when the measured sound is above65 dB (SPL 1 Trigger Level) for at least 4 seconds (Trigger Time) theevent recording would include 11 seconds of sound (Pre-trigger +Snapshot Time).

FIGURE 18-4 Sound Event Live Example

TAKE NOTE If a second event (such as a measurement history or manually triggered sound recording) begins during an ongoing sound recording, the sound recording extends. This continues until there are no more events. When you examine the recording after the measurement, you will find that the sound recording is associated to the first event even though it contains sound recordings for the subsequent events.

1 .3.1 About Sound Recording Constraints

If you set the Minimum Duration and Pre-trigger values to be greaterthan the filter constraints, an error message appears and the valuesautomatically adjust.

a le 1 1 displays the maximum values you can indicate for theMinimum Duration (Event History) and Pre-trigger (Sound) whenusing automated Event Sound Recording.

TAKE NOTE The 51.2 ksps sample rate serves a unique function— when used with Time History records, the sound recording and the Time History record are synced. At any other sample rate, filter delays prevent this time synchronization.

If you monitor the measurement, notice that the record icon changes from gray to red during the designated Snapshot Time.

Table 18.1 Sound Recording Constraints

Sample RateMinimum Duration

Pre Trigger

8 ksps 60 s

16 ksps 30 s

24 ksps 20 s

48 ksps 10 s

SoundAdvisor Model 831C Enabling Measurement History Sound Recording 18-5

18.4 Enabling Measurement History Sound RecordingWith both 831C-ELA and 831C-SR, or 831C-MSR, firmware optionsinstalled, you can set up the 831C to automatically initiate a soundrecording snapshot at the beginning of each measurement historyperiod.

Before you begin:• Open the Setup Manager (Tools Setup Manager) and create a

setup file with Measurement History enabled, as shown in 15.1Setting Up a Measurement ith Measurement History.

Step 1 Go to Tools Setup Manager and highlight the name of a measurementhistory enabled setup file. Before saving the Setup, press the top-leftsoftkey (*//) to open the Sound tab.

Step 2 Select a sound recording Range value. For more information about thisand other values on the Sound page, which affect the quality of therecording, see 18.5 Understanding Recording Settings and SoundQuality.

Step 3 Select the checkbox in-line with Save Measurement Sound, and enter aSnapshot Time.

FIGURE 18-5 Measurement Sound Tab

51.2 ksps 9.375 s

Table 18.1 Sound Recording Constraints

Sample RateMinimum Duration

Pre Trigger

For important, related information, see 18.5 Understanding Recording Settings and Sound Quality.

The measurement sound Snapshot Time ( 9999 s) is the time in seconds that will record at the beginning of each measurement interval.

If you select Compression, sound recordings are saved in OGG format. See 18.5.3 Choosing a File Format for Sound Records.

When you select Save Measurement Sound, the resulting data file saves a sound recording at the beginning of each measurement history interval.

SoundAdvisor Model 831C Understanding Recording Settings and Sound Quality 18-6

Step 4 Select Close (/*/), save the Setup, then select it again and Set toActive.

Step 5 Close the Setup and run a measurement. Based on the settings in Figure18-5 Measurement Sound Tab, the first 5 seconds of each measurementinterval would be recorded.

18.5 Understanding Recording Settings and Sound QualityIn this section:

• 18.5.1 Understanding Resolution, Peak Overload

• 18.5.3 Choosing a File Format for Sound Records

• 18.5.3 Choosing a File Format for Sound Records

18.5.1 Understanding Resolution, Peak Overload

ResolutionSound recordings are saved with 16-bit resolution which provides ameasurement range of about 90 dB. This means that the 831C iscapable of recording sound signals with amplitudes no more than 90dB below the level at which the selected range will overload.

Peak OverloadThe 831C will calculate the peak overload based on the currentmicrophone type. To ensure the correct settings, navigate to Tools Calibrate Settings, and see 5.4 Calibrating Your SoundAdvisor831C.

Next, the 831C automatically calculates the sound recording rangebased on the Peak Overload value. Additionally, setting the Gain ateither 0 dB or 20 dB (Menu Setup Manager SLM) and selectingeither Normal or High Range (Menu Setup Manager Sound) willresult in different values of upper and lower limits for any givenmicrophone. The current Peak Overload value displays on the calibratetab as shown in Figure 18-6 Peak Overload.

SoundAdvisor Model 831C Understanding Recording Settings and Sound uality 18-7

FIGURE 18-6 Peak Overload

1 .5.2 Selecting an Appropriate Sound Recording Range

To select a sound recording range on the 831C, go to Menu SetupManager Sound.

We recommend using the Normal range for sound recordings unlessyou anticipate that recorded sounds will exceed 110dBA. In that case,choose High range.

1 .5.3 Choosing a ile ormat for Sound Records

To choose compressed or uncompressed sound records on the 831C, goto Menu Setup Manager Sound.

Sound recordings are saved in WAV format (uncompressed) unless youselect the Compression checkbox. The compression setting savessound records in OGG format. This compressed format is mostportable—easily shared over email and text or as an alert notification.However, it may also truncate OBA or other types of data.

While a WAV file requires much more space, this format preservesfrequency detail best. If you plan to examine octave bands or specificfrequencies of a sound recording, we recommend using the WAVformat.

The following table describes the approximate file size for a 60-secondsound recording. The WAV file sizes in Table 18.2 are accurate to thenearest 50 kB. The OGG file sizes are approximations since everycompressed file will be unique.

Table 18.2 Sound Recording File Sizes Per 60 Seconds

Sample Rate A O

8 ksps 0.96 MB 200 kB

16 ksps 1.98 MB 350 kB

24 ksps 2.88 MB 450 kB

SoundAdvisor Model 831C Sound Recording Playback 18-8

Event sound recordings are available to play back directly on the 831Cuntil you save the data file. After that, you can most easily access thesound recordings from the G4 LD Utility software.

18.6 Sound Recording PlaybackIn this section:

• 18.6.1 Playback on the 831C

• 18.6.2 Playback After Saving in G4

1 .6.1 Playback on the 31C

Until you save the data file, you can play sound recordings directly fromthe 831C.

Step 1 Connect a USB-compatible headset or speaker to the 831C.

Step 2 Use the top-left softkey (*//)to open the Session Log tab, and select asound event from the list. This opens the sound player.

FIGURE 18-7 Session Log Playback

1 .6.2 Playback After Saving in G4

After the sound recording is stored, you can access it most easily fromthe G4 LD Utility.

LEARN MORE For more information, see section A.4 Audio Files and Streaming in the G4 LD Utility Reference Manual.

48 ksps 5.67 MB 600 kB

51.2 ksps 6.14 MB 650 kB

Table 18.2 Sound Recording File Sizes Per 60 Seconds

Sample Rate A O

SoundAdvisor Model 831C A-1

Appendix A Technical SpecificationsA.1 Instrument Platform ...........................................................................................................A-1

A.2 Base Software ......................................................................................................................A-6

A.3 Octave Band Analysis Software – Option 831C-OB3 .........................................................A-9

A.4 Event Logging Software – Option 831C-ELA ....................................................................A-15

A.5 Time History Software – Option 831C-LOG ......................................................................A-16

A.6 PTB Approved Firmware ...................................................................................................A-16

A.7 Frequency Response .........................................................................................................A-17A.7.1 Plane Parallel To Display Screen .......................................................................A-17A.7.2 Perpendicular to Plane of Display Screen .........................................................A-26A.7.3 Random Incidence ..............................................................................................A-34A.7.4 Typical Z-Weight Frequency Response ..............................................................A-35

A.8 Declaration of Conformity ................................................................................................A-36

Unle t er i e n te t e e ecificati n a ly t t e un i r M el 1 LM u e it a 77 0icr ne RM 1 icr ne rea lifier an t e 0 0 0 f t rea lifier e ten i n ca le

A.1 Instrument Platform

Supplied MicrophoneModel 377B02, ½-inch free-field, prepolarized condenser microphoneTypical Sensitivity: 50 mV/Pa (+/-1.5 dB) corresponding to -26 dB re. 1 V/PaFre uency Response: 3 1 Hz to kHz ( / dB)Capacitance: 1 pFMicrophone PreamplifierModel PRM831, 1/2” diameter x 2.88”

Standards MetSafety: IEC 61010-1:2010: Safety Requirements forElectrical Equipment for Measurement, Controland Laboratory UseEMC Emission:CISPR 11:2015 with Amend 1 (EN 55011)EMC Immunity: EN 61672-1:2013, EN 61000-6-2:2005Electrostatic discharge (ESD) Immunity:IEC61000-4-2:2008, 4kV contact discharges and 8 kV air discharges.Other Standards:Test results and certificates compliant with ISO17025

Table A.1 Safety Marks

CE-mark indicates compliance with the

EMC, Low Voltage, and RoHs Directives

cUL/UL and SAA

WEEE mark indicates compliance with the EU

WEEE Directive


Typical Preamplifier Attenuation: 0.08 dBConnector: 5-Pin Male, Switchcraft TA5MLAUXMating Connector: 5-Pin Female, SwitchcraftTA5FLAUXExtension Cables: You can use a preamplifierextension cable between the meter and the

preamplifier/microphone with no degradation forlengths up to 200 feet (61 m).Microphone polarization voltage: 0 V (nopolarization is provided, so use pre-polarizedmicrophones)

SLM PerformanceTable A.2 SLM Performance (Nominal Values)

PRM831 with 377B02

Microphone (dB)

Direct Input (dBµV)

PRM831 with 377A15 (dB)

Gain 0 dB +20 dB 0 dB +20 dB 0 dB +20 dB

Measurement Range1

1. Microphone and electrical self-noise included

A 24-140 20-120 n/a n/a 21-140 16-120

C 26-140 25-120 n/a n/a 21-140 16-120

Z 36-140 33-120 n/a n/a 27-140 25-120

Typical Noise Floor1

A 16.3 15.6 8.3 -0.1 13.8 12.5

C 16.8 16.3 6.9 -1.4 14.3 13.8

Z 23.4 23.2 12.3 3.0 23.0 22.8

Linearity Range2

2. Electrical measurement, frequency 1kHz

A≥117 ≥102 ≥120 ≥108 ≥120 ≥106

23-140 18-120 20-140 12-120 20-140 14-120

C≥114 ≥96 ≥121 ≥110 ≥120 ≥106

25-140 24-120 19-140 10-120 20-140 14-120

Z≥104 ≥87 ≥117 ≥104 ≥114 ≥96

36-140 35-120 23-140 15-120 26-140 24-120

Peak Range2

A 65-143 44-123 65-143 46-123 64-143 45-123

C 66-143 45-123 63-143 46-123 65-143 46-123

Z 68-143 59-123 64-143 46-123 66-143 48-123

SPL Max Level2 ≥140 ≥120 ≥140 ≥120 ≥140 ≥120

Peak Max Level2 ≥143 ≥123 ≥143 ≥123 ≥143 ≥123


User InterfaceKeyboard: 13 keys, quiet elastomer touch withblue back-lighting for measurement control anddata navigationStatus Indicators:

• Red LED under the STOP/STORE keyindicates measurement stopped

• Green LED under the RUN/PAUSE keyindicates measurement running

• Green LED under the power key indicatesbattery charge and power on/off inprogress

Display: • TFT full color LCD, 240 by 320 dot matrix• White backlight with adjustable brightness

and on–time• Touch screen to assist in data navigation

and measurement control• Multiple color themes for various lighting

conditionsDisplay update rate: ≤ 1 sLock: User interface may be locked and unlockedLanguages: Czech, English, French, German,Italian, Norwegian, Portuguese, Russian, Spanish,Swedish, Turkish

InputConnector: Latching 5-pin circular connector,mates to PRM831 or EXCxxx cablesPreamplifier Supply: 36 volt at 5mA available topower preamplifierInput Impedance: ≥ 100kΩ || 300 pFDirect Input: Absolute maximum of ±35 V, DC biasreadout 0 to +35 VGain Control: Selectable 0 or +20 dB gainFull Scale Input 0 dB Gain: ±14.14 Vpeak ACFull Scale Input +20 dB Gain: ±1.414 Vpeak ACICP Input (use ADP074): Constant current of 4mA, maximum voltage of 28 VSample Rate: 51,200 sps

USB Client InterfaceType: USB 2.0 High–Speed Mini–B connectorPower Draw: ≤ 500mA from PC, USB Hub, orPSA029Supported Hosts:

• Computer with SLM Utility-G4• Ethernet Dock 831INT-ET• NoiseTutor• Computer with custom software using

SWW-G4-SDK or SWW-G4-WIN

USB Host InterfaceType: USB 2.0 High-Speed, standard A connectorSupported Devices:

• USB Flash Memory Drive, up to 32GB FAT-32Format, PN 831-M

• Ethernet Adapter, 1G/100M/10M, PNDVX012

• Ethernet Adapter & USB Hub, 1G/100M/10M, PN DVX013

• WiFi Wireless Adapter, Edimax EW-7811Un,or D-Link DWA-121, PN DVX014 (WPA/WPA2encryption)

• GPS Receiver HOLUX M-215, PN GPS001• Multi–Metric Weather Sensor, Vaisala

WXT520, PN SEN031• Ultrasonic Wind Sensor, Vaisala WMT52, PN

SEN032• Wireless LTE Gateway, Sierra Wireless

AirLink RV-50, PN COM-RV50-DC-E or COM-RV50-DC-U

AC/DC OutputConnector: 2.5mm (3/16”) Sub-Miniature PhoneJack, AC Output on RING, DC Output on TIPAC Output Selections: (1) Off, (2) 0 dB, (3) +20 dB,(4) +40 dB, and (5) Preamp 10VGains of 0, +20 and +40 are relative tomeasurement full scale.AC Output Voltage: For 0 dB through +40 dBselection: ±2.12 Vpeak Maximum (-16.5dB re. toinput), suitable for LINE inputsFor Preamp selection: ±14.14 Vpeak MaximumAC Output Impedance: 1kΩ || 1000pFAC Output Frequency Weighting: No frequencyweighting is applied. Includes input's 0.1Hz high-pass filter onlyDC Output Voltage: 10 mV/dB, +2.2 V maximum,0V ≈ 0dB & 2V ≈ 200dBDC Output Impedance: 1kΩ || 1000pFNote: DC Output only while meter is running


AC Performance

I/O ConnectorProvides External Power, Analog and Digital I/O,and enhanced capabilities for 831-INTMating connector: Hirose ST40X-18S or ST60X-18SLogic Output: Output driven 0 to +3V through1kΩ, setting selects functionLogic Input: Input accepts 0 to +3.3V, ≈50kΩ load,setting selects functionExternal Power: +10 to +25 V, 500mA, selfresetting fuseDigital Sensor Port: Synchronous serial port forPRM2103 and 426A12 metricsPreamplifier Control: Digital control lines forpreamplifier calibration check and overloaddetectionWindspeed Pulse Input: Input accepts 0 to +3pulses from anemometer (+5V tolerant), 100kΩload, setting selects functionAnalog Inputs: 3 channels, 0 to +2.5 V, 100kΩ load,settings for scale and offset

I/O Connector PinoutsThe pinouts for the I/O Connector are as shownbelow:

1. To enable the “Logic In, Logic Control Input” fea-ture, when making your own cable, pin 12 (Mains Power Status) must be driven by a resistance lower than about 20k. This may be done by con-necting a 10k resistor from pin 12 to either pin 13 (+2.5V, to simulate running on Mains power) or to pin 1 or 5 (Ground, to indicate running on external battery power). Pin 4 needs to be driven high to assert the Logic In and pulled low to de-assert the input. It should not be left floating. This can be done with a momentary push-button switch from pin 4 to pin 13 with a 10k pull down resistor to ground (10k from pin 4 to pin 1 or 5).

BatterySize: 4 x AA size cells (LR6)Types: 1.5 V Alkaline, 1.2 V NiMH rechargeable, 1.5V Photo–Lithium

0 dB Gain 20 dB Gain

AC Output Setting

Output re input (dB)

Maximum* (dB re 20

µPa)

Maximum* (dB re 20

µPa)

Off Off Off Off

Out + 0 dB -16.5 140 120

Out +20 dB -36.5 120 100

Out +40 dB -56.5 100 80

Preamp 10V 0.0 140 120

* Results for typical 377B02 microphone, actually sensitivity effects results

Pin # Description Signal Type

1 Ground, Digital and Power Supply

Ground

2 Logic Out 1, Logic Control Output

Output, 0 to +2.7 V

3 831 Activity Output, 0 to +2.7 V

4 Logic In, Logic Control Input Input, 0 to +5 V

5 Ground, Digital and Power Supply

Ground

6, 7 Vext, External Power Input Input, +10.8 to +30 V, 0.5 A

auto-resetting PTC fuse

8 SensorClk_L, LD 426A12 digital sensor clock

Output, open drain, +20 V max. open and 50 mA

max. closed

9 SensorDIO, LD 426A12 digital sensor data

Bi-directional, +2.7 to +5 V logic, open

drain

10 CalOn_H, LD 426A12 calibration signal on

Output, 0 to +2.7 V

11 Ovld, LD 426A12 overload detection signal

Input, 0 to +5 V

12 Mains Power Status; OK when +2.7 V

Input, 0 to +2.7 V

13 +2.7 V to supply logic switches

Output, +2.7 V through 220

14 Wind Speed In, Pulse input for wind speed sensors

Input, +5 Vpp max.

15 Vwthr1, Analog to Digital Converter Input, Wind

Direction

Input, 0 to +2.048 V, 100k load, scale with series resistor

16 Vwthr2, Analog to Digital Converter Input,

Temperature

17 Vwthr3, Analog to Digital Converter Input, Humidity

18 Analog Ground, Signal ground for pins 15 through

17

Ground

Pin # Description Signal Type


NiMH Charge Time: USB to power outlet (not PC),meter powered OFF during charging 16 hoursTypical Operating Time: 8 hours continuousmeasurement

E ternal PowerVia USB Client Connector: Powered by computeror PSA029 Power Adapter, 5.0 0.5 V typical, 16 Vabsolute maximum

E ternal DC Power SupplyProvides power to operate instrument, supply USBHost port with 500mA, and charge batteriesRecommended Supplies: Use cable CBL140 withPSA027, CBL154 for 426A12, or Model 831-INTInterface with Mains and battery suppliesVoltage: +10 to +25 VSupply Current Re uirement: 1.0 A minimumPower Consumption: 1.1 W (display off, running,no USB Host devices, not charging)2 W (display & backlight on, no USB Host devices,not charging)

5.4 W (with 2.5 W USB Host power and charging)Accessory Power Consumption: 831-MEM32G USB Memory, 32GB: +0.6 WDV 012 Ethernet Adaptor: +1.8 WDV 014 WiFi Adapter: +0.7 W

Power on Time 2 minutes

Real Time ClockDrift 0.3 s drift per 24 hour period over fulloperating temperature range, battery back-uppoweredBackup Time 1 year rechargeable battery backup

Data StorageInternal: 2 GB non-volatile flash memorydedicated to data and user setupsExternal: Up to 32 gigabyte USB Flash MemoryDrive

Electrostatic DischargeThe instrument is not adversely affected byelectrostatic discharges.

En ironmental ConditionsOperating Temperature: –30 to +50°C (–22 to122°F)

Table A.3 Low Power At oot Up

Power Level

Power Source Parameters Icon Action

Low

External External Shutoff

Voltage1 + 0.8 V

Warning Only

Internal 4.2 V

Very

Low

External External Shutoff Voltage+ 0.5 V

Halts boot-up process2

Internal 4.1 V Halts boot-up process

and shuts down.

Dead

External External Shutoff Voltage - 0.2 V

N/A Aborts boot-up

and shuts down.Internal 3.8 V N/A

1. The External Shutoff Voltage is a user defined set-ting, see 9.4.6 Setting the External Shutoff Volt-age on page 9-5

2. The boot up process halts for one minute, if power is not restored within one minute, then the meter will shut off for a period of time before powering back on. When the meter powers back on is deter-mined by the number of times trying to boot with failed power, see Table A.4.

Table A.4 Power On After E ternal Power Fail Schedule

Powers On Time Since Last Power Fail

1st Attempt 20 minutes

2nd Attempt 1 hour

3rd Attempt 2 hours

4th Attempt 4 hours

5th Attempt 6 hours

6th Attempt 12 hours

7th - 16th Attempt 24 hours

Table A.3 Low Power At oot Up Continued

Power Level

Power Source Parameters Icon Action


Storage Environment: –30 to +60° C (–22 to+158°F), less than 90% RHTemperature Sensitivity: ≤ 0.5 dB sensitivity, –10to +50°C (14 to 122°F) at 1kHzHumidity Sensitivity: ≤ ±0.5 dB sensitivity, 25% to90% relative humidity at 40°C (104°F) at 1kHz

Physical CharacteristicsDimensions:

• 290 x 71 x 41 mm (11.35") includingmicrophone and preamplifier

• 224 x 71 x 41 mm (8.80") instrument bodyonly

Weight:• 531.6 g (18.8 oz) including batteries,

preamplifier and microphone• 489.2 g (17.3 oz) including batteries

A.2 Base SoftwareStandards MetSound Level Standards:

• IEC 61672-1:2013 Class 1, Group X• IEC 60651 Ed 1.2 (2001) plus Amendment 1

(1993-02) and Amendment 2 (2000-10) Type1, Group X

• IEC 60804 (2000-10) Type 1, Group X• ANSI S1.4-2014 Class 1• ANSI S1.4-1983 (R2006) plus Amendment

ANSI S1.4A-1985 (R2006) Type 1• ANSI S1.43-1997 (R2007) Type 1• DIN 45657 Sound level meters - Additional

requirements for special measuring tasks

Correction Filters• Frequency response correction filters are

available for sound field/microphone typeand for environmental protectionaccessories.

• Note: “RI” indicates “Random Incidence”and “FF” indicates “Free-Field”

• For microphone 377B20: RI to FF• For microphone 377B02: FF to RI• For microphone 377B02 with EPS2106/8: FF

to RI, FF to FF, FF:90°• For microphone 377B02 with EPS2116: FF

to RI, FF to FF, FF:90°Table A.5 SLM with PRM831 and 377B02 Microphone

Frequency0° Free Field

Corrections1,2

1. add numbers in this column to levels read on the SLM to correct to the 0° Free Field level at frequency2. From B&K 4226 Calibrator3. From B&K UA033 EA4. Corrections at 95% confidence.EA - Electrostatic ActuatorWS - WindscreenNote: Data was taken at reference conditions 23° C, 50% RH, 101.3 kPa

0° Free Field Corrections with

WS1,2

0° Free Field Corrections1,3

0° Free Field Corrections with

WS1,3

Expanded uncertainty of Corrections 1,4

Hz dB re 1 kHz dB re 1 kHz dB re 1 kHz dB re 1 kHz dB

31.5 0.23 0.12 0.21 0.10 0.25

63 0.18 0.07 0.15 0.04 0.25

125 0.09 -0.02 0.10 -0.01 0.25

250 0.10 -0.01 0.07 -0.03 0.25

500 0.25 0.17 0.26 0.18 0.25

1000 0.00 0.00 0.00 0.00 0.25

2000 0.43 0.69 0.42 0.69 0.25

4000 0.97 0.94 0.97 0.95 0.25

8000 2.60 2.25 3.02 2.67 0.35

12500 5.65 5.33 6.51 6.19 0.50

16000 7.69 6.92 8.46 7.68 0.50


Measurement SystemIntegration Method:

• Equivalent level integration method can beLinear or Exponential.

• Exponential integrates the output of theselected time weighting (Slow, Fast orImpulse)

Integration Time: • Minimum: 0.1 s• Maximum, <0.5dB error: > 23 days

Frequency Weightings: A, C, Z parallel andsimultaneous for each Time Weighting, selectedfrequency weighting (A, C or Z) indicated by Peak Frequency Weightings: A, C, Z parallel,selected peak frequency weighting (A, C or Z)indicated by Time Weightings/Detectors: Slow, Fast, Impulse,Linear and Peak simultaneously, selected timeweighting (S, F or I) indicated by Peak Rise Time: 30 µs

MeasurementsInstantaneous “Live” MetricsFor display and profile graph, not stored withmeasurement. A primary frequency and time weighting isselected by setting for RMS and Peak level todisplay, all levels are available in an “Any Level”matrix.

Overall MetricsA primary frequency and time weighting isselected by setting for RMS and Peak level todisplay, all levels are available in an “Any Level”matrix.

Occurrence Time for Minimum and MaximumLevels

Percentile Levels, percentages n1 through n6selectable, 0.01 to 99.99%Statistics are sampled every 10ms from theselected frequency and time weighted detector.

Time Weighting A C Z Units

Linear LAeq LCeq LZeq dB

Slow LAS LCS LZS dB

Fast LAF LCF LZF dB

Impulse LAI LCI LZI dB

Peak LApeak LCpeak LZpeak dB


Linear1 LAeq LCeq LZeq dB

Linear2 LAƬeq LCƬeq LZƬeq dB

1. Linear integration method selected by user2. Exponential Integration method selected by user

Slow Maximum

LASmin LCSmin LZSmin dB

Slow Minimum

LASmax LCSmax LZSmax dB

Fast Minimum

LAFmin LCFmin LZFmin dB

Fast Maximum

LAFmax LCFmax LZFmax dB

Impulse Minimum

LAImin LCImin LZImin dB

Impulse Maximum

LAImax LCImax LZImax dB

Peak LApeak(max) LCpeak(max) LZpeak(max) dB


Slow Maximum

TASmin TCSmin TZSmin y/m/d h:m:s

Slow Minimum

TASmax TCSmax TZSmax y/m/d h:m:s

Fast Minimum

TAFmin TCFmin TZFmin y/m/d h:m:s

Fast Maximum

TAFmax TCFmax TZFmax y/m/d h:m:s

Impulse Minimum

TAImin TCImin TZImin y/m/d h:m:s

Impulse Maximum

TAImax TCImax TZImax y/m/d h:m:s

Peak TApeak(max) TCpeak(max) TZpeak(max) y/m/d h:m:s

Units

1 LωƬn1 dB

2 LωƬn2 dB

3 LωƬn3 dB

4 LωƬn4 dB

5 LωƬn5 dB

1. Linear integration method selected by user2. Exponential Integration method selected by user


Exceedance Metrics, exceedance levels (L1, L2, P1,P2 and P3) selectable in dB from 0.0 to 200.0,counts each time the level rises above thethreshold and measure the duration while abovethe level minus 2dB.

Overload count and duration metrics• Occurrences, count from 0 to 99999: nnnnn• Overload Percentage: nnn.nn %• Duration Overloaded: h:m:s.s• Elapsed Run-Time: h:m:s.s• Elapsed Pause-Time: h:m:s.s

Community Noise• Day Night Level, midnight to midnight

• LDN• Daytime portion of Day Night Level

• Lday (Tday - Tnight)• Nighttime portion of Day Night Level

• LNight (Tnight - Tday)• Day Evening Night Level, midnight to

midnight• LDEN

• Daytime portion of Day Night Level• LDay (Tday - Teve)

• Evening-time portion of Day Night Level• LEve (Teve - Tnight)

• Nighttime portion of Day Night Level• LNight (Tnight - Tday)

C minus Amathematical subtraction of C and A weightedequivalent levels

ImpulsivityMathematical subtraction of impulse and linearequivalent levels

Location, GPS (internal or external GPS, recordslast fix of measurement):

• Latitude: dg m.m• Longitude: dg m.m• Elevation: m or feet• Time Acquired: h:m:s

Measurement ControlMultiple control modes provide for manual andautomated measurementsManual: Manually control measurements-- RUN,PAUSE, RESUME, STOP, STORETimed Stop: Start manually and runs for set runtime (1 second to 99 hours)Stop When Stable: Start manually and runs untillevels are stableContinuous: Start manually or at power on andruns without interruption, Daily Auto-Storeavailable, special restart after low battery featuresenabledSingle Block Timer: Runs from a set date and timeto another date and timeDaily Timer: Runs for up to three time blocks perday qualified by a start date and an end date

Measurement StatusMeasurement status is indicated on the displayand with lights below the STOP and RUN keys.Stopped Reset, Stopped, Run, Paused, Stored,StandbyIcons on display indicate Overload, battery stateand memory status.

Back–EraseErase the previous five or ten seconds from ameasurement.

6 LωƬn6 dB

Label Count Duration

SPL 1 LωƬ > L1 0 to 99999 h:m:s.s

SPL 2 LωƬ > L2 0 to 99999 h:m:s.s

Peak 1 LωƬ > P1 0 to 99999 h:m:s.s



Linear Exponential Units

LAeq - Laeq LAƬeq - LaƬeq dB


LAIeq - LAeq dB


A.3 Octave Band Analysis Software – Option 831C-OB3Standards MetOctave Filter Standards: IEC 61260-1:2014/Part 1,1/1 and 1/3-octave Bands, Class 1, Group X, allfiltersANSI/ASA S1.11-2014/Part 1, 1/1 and 1/3-octaveBands, Class 1, Group X, all filters

Bandwidth1/1 Octave, 1/3 Octave, or simultaneous 1/1 and 1/3 Octave

Filter Type and Sample RateDigital filters are sampled at a rate of 51,200samples per second, with base 10 centerfrequencies and have real-time performance for allfilters. The 0 dB gain setting and “high” OBA range

is the reference range and the reference inputsignal is .5 Volt rms at 1 kHz.

1/1 Octave Center Frequencies8 Hz to 16 kHz

1/3 Octave Center Frequencies6.3 Hz to 20 kHz

Measurement RangeNormal (107 dB full scale) and High (140 dB fullscale). Note: These ranges assume a 50 mV/Pamicrophone is being used.

Filter Shape1/3 octave band centered at 1 kHz. Overlaid withthe Class 1 limit curves.

FIGURE A-1 Filter Shape-20.0

0.0

20.0

40.0

60.0

80.0

100.0

120.0100.0 1000.0 10000.0

Atte

nuat

ion

Frequency Hz

1 kHz FilterLower LimitUpper Limit


Filter Linearity

Table A.6 Octave Band Analysis 1/1 Octave Linearity Range

Nominal Frequency

(Hz)High OBA Range Normal OBA Range

Nominal Frequency

(Hz)High OBA Range Normal OBA Range

0 dB Gain (dB)

+20 dB Gain (dB)

0 dB Gain (µdB)

+20 dB Gain (dB)

0 dB Gain (dB)

+20 dB Gain (µdB)

0 dB Gain (µdB)

+20 dB Gain (µdB)

PRM

831

8.0 ≥ 10832 to 140

≥ 8931 to 120

≥ 8030 to 110

≥ 6130 to 90

Dire

ct In

put

8.0 ≥ 102110 to 39

≥ 9823 to 120

≥ 1019 to 110

≥ 891 to 90

16.0 ≥ 11030 to 140

≥ 9228 to 120

≥ 8327 to 110

≥ 6427 to 90

16.0 ≥ 108110 to 32

≥ 10614 to 120

≥ 1082 to 110

≥ 92-2 to 90

31.5 ≥ 11229 to 140

≥ 9526 to 120

≥ 8625 to 110

≥ 6624 to 90

31.5 ≥ 120110 to 20

≥ 1183 to 120

≥ 111-1 to 110

≥ 96-6 to 90

63.0 ≥ 11327 to 140

≥ 9723 to 120

≥ 8822 to 110

≥ 6921 to 90

63.0 ≥ 119110 to 22

≥ 1173 to 120

≥ 1100 to 110

≥ 95-5 to 90

125 ≥ 11327 to 140

≥ 10020 to 120

≥ 9119 to 110

≥ 7318 to 90

125 ≥ 117110 to 24

≥ 1155 to 120

≥ 1082 to 110

≥ 94-4 to 90

250 ≥ 11327 to 140

≥ 10317 to 120

≥ 9416 to 110

≥ 7615 to 90

250 ≥ 115110 to 26

≥ 1137 to 120

≥ 1064 to 110

≥ 93-3 to 90

500 ≥ 11129 to 140

≥ 10515 to 120

≥ 9614 to 110

≥ 7813 to 90

500 ≥ 112110 to 28

≥ 1119 to 120

≥ 1046 to 110

≥ 91-1 to 90

1000 ≥ 10931 to 140

≥ 10515 to 120

≥ 9714 to 110

≥ 7912 to 90

1000 ≥ 109110 to 31

≥ 10912 to 120

≥ 1019 to 110

≥ 882 to 90

2000 ≥ 10634 to 140

≥ 10416 to 120

≥ 9615 to 110

≥ 7911 to 90

2000 ≥ 106110 to 34

≥ 10615 to 120

≥ 9812 to 110

≥ 865 to 90

4000 ≥ 10337 to 140

≥ 10218 to 120

≥ 9317 to 110

≥ 7812 to 90

4000 ≥ 103110 to 37

≥ 10318 to 120

≥ 9515 to 110

≥ 838 to 90

8000 ≥ 10040 to 140

≥ 9921 to 120

≥ 9120 to 110

≥ 7614 to 90

8000 ≥ 100110 to 40

≥ 10021 to 120

≥ 9219 to 110

≥ 8011 to 90

16000 ≥ 9743 to 140

≥ 9624 to 120

≥ 8823 to 110

≥ 7417 to 90

16000 ≥ 97110 to 43

≥ 9624 to 120

≥ 8822 to 110

≥ 7714 to 90


Table A.7 Octave Band Analysis 1/3 Octave Linearity RangeNominal

Frequency (Hz)

High OBA Range Normal OBA RangeNominal

Frequency (Hz)

High OBA Range Normal OBA Range

0 dB Gain (dB)

+20 dB Gain (dB)

0 dB Gain (µdB)

+20 dB Gain (dB)

0 dB Gain (dB)

+20 dB Gain (µdB)

0 dB Gain (µdB)

+20 dB Gain (µdB)

PRM

831

6.3 ≥ 10734 to 140

≥ 9031 to 120

≥ 8129 to 110

≥ 6228 to 90

Dire

ct In

put

6.3 ≥ 9941 to 140

≥ 9724 to 120

≥ 1046 to 110

≥ 864 to 90

8.0 ≥ 10832 to 140

≥ 9129 to 120

≥ 8228 to 110

≥ 6327 to 90

8.0 ≥ 10239 to 140

≥ 10021 to 120

≥ 1064 to 110

≥ 900 to 90

10.0 ≥ 11030 to 140

≥ 9228 to 120

≥ 8327 to 110

≥ 6426 to 90

10.0 ≥ 10436 to 140

≥ 10119 to 120

≥ 1091 to 110

≥ 92-2 to 90

12.5 ≥ 11129 to 140

≥ 9327 to 120

≥ 8525 to 110

≥ 6525 to 90

12.5 ≥ 10634 to 140

≥ 10218 to 120

≥ 1100 to 110

≥ 93-3 to 90

16.0 ≥ 11228 to 140

≥ 9426 to 120

≥ 8624 to 110

≥ 6624 to 90

16.0 ≥ 10833 to 140

≥ 10515 to 120

≥ 111-1 to 110

≥ 94-4 to 90

20.0 ≥ 11427 to 140

≥ 9525 to 120

≥ 8724 to 110

≥ 6723 to 90

20.0 ≥ 12318 to 140

≥ 1155 to 120

≥ 112-2 to 110

≥ 95-5 to 90

25.0 ≥ 11525 to 140

≥ 9624 to 120

≥ 8823 to 110

≥ 6822 to 90

25.0 ≥ 12516 to 140

≥ 121-1 to 120

≥ 113-3 to 110

≥ 95-5 to 90

31.5 ≥ 11624 to 140

≥ 9723 to 120

≥ 8922 to 110

≥ 6921 to 90

31.5 ≥ 12416 to 140

≥ 122-2 to 120

≥ 114-4 to 110

≥ 96-6 to 90

40.0 ≥ 11723 to 140

≥ 9922 to 120

≥ 9021 to 110

≥ 7020 to 90

40.0 ≥ 12317 to 140

≥ 122-2 to 120

≥ 114-4 to 110

≥ 97-7 to 90

50.0 ≥ 11822 to 140

≥ 10021 to 120

≥ 9120 to 110

≥ 7119 to 90

50.0 ≥ 12318 to 140

≥ 121-1 to 120

≥ 113-3 to 110

≥ 97-7 to 90

63.0 ≥ 11922 to 140

≥ 10120 to 120

≥ 9119 to 110

≥ 7218 to 90

63.0 ≥ 12218 to 140

≥ 121-1 to 120

≥ 112-2 to 110

≥ 97-7 to 90

80.0 ≥ 12021 to 140

≥ 10219 to 120

≥ 9218 to 110

≥ 7317 to 90

80.0 ≥ 12219 to 140

≥ 1200 to 120

≥ 112-2 to 110

≥ 98-8 to 90

100 ≥ 12020 to 140

≥ 10318 to 120

≥ 9417 to 110

≥ 7416 to 90

100 ≥ 12119 to 140

≥ 1191 to 120

≥ 111-1 to 110

≥ 98-8 to 90

125 ≥ 12120 to 140

≥ 10417 to 120

≥ 9516 to 110

≥ 7515 to 90

125 ≥ 12020 to 140

≥ 1192 to 120

≥ 111-1 to 110

≥ 99-9 to 90

160 ≥ 12120 to 140

≥ 10516 to 120

≥ 9615 to 110

≥ 7614 to 90

160 ≥ 11921 to 140

≥ 1182 to 120

≥ 1100 to 110

≥ 99-9 to 90

200 ≥ 12020 to 140

≥ 10615 to 120

≥ 9714 to 110

≥ 7713 to 90

200 ≥ 11922 to 140

≥ 1182 to 120

≥ 1101 to 110

≥ 99-9 to 90

250 ≥ 11921 to 140

≥ 10714 to 120

≥ 9812 to 110

≥ 7911 to 90

250 ≥ 11822 to 140

≥ 1173 to 120

≥ 1091 to 110

≥ 98-8 to 90

315 ≥ 11922 to 140

≥ 10813 to 120

≥ 9911 to 110

≥ 8010 to 90

315 ≥ 11723 to 140

≥ 1174 to 120

≥ 1091 to 110

≥ 97-7 to 90

400 ≥ 11823 to 140

≥ 10912 to 120

≥ 10010 to 110

≥ 819 to 90

400 ≥ 11724 to 140

≥ 1164 to 120

≥ 1082 to 110

≥ 96-6 to 90

500 ≥ 11723 to 140

≥ 11011 to 120

≥ 1019 to 110

≥ 828 to 90

500 ≥ 11624 to 140

≥ 1164 to 120

≥ 1083 to 110

≥ 95-5 to 90

630 ≥ 11624 to 140

≥ 11010 to 120

≥ 1019 to 110

≥ 837 to 90

630 ≥ 11525 to 140

≥ 1155 to 120

≥ 1073 to 110

≥ 94-4 to 90

800 ≥ 11525 to 140

≥ 11010 to 120

≥ 1029 to 110

≥ 847 to 90

800 ≥ 11526 to 140

≥ 1146 to 120

≥ 1064 to 110

≥ 94-4 to 90

1000 ≥ 11427 to 140

≥ 11010 to 120

≥ 1029 to 110

≥ 846 to 90

1000 ≥ 11427 to 140

≥ 1137 to 120

≥ 1055 to 110

≥ 93-3 to 90

1250 ≥ 11327 to 140

≥ 11010 to 120

≥ 1029 to 110

≥ 856 to 90

1250 ≥ 11327 to 140

≥ 1128 to 120

≥ 1046 to 110

≥ 92-2 to 90

1600 ≥ 11229 to 140

≥ 10911 to 120

≥ 1019 to 110

≥ 855 to 90

1600 ≥ 11129 to 140

≥ 1119 to 120

≥ 1037 to 110

≥ 91-1 to 90

2000 ≥ 11129 to 140

≥ 10912 to 120

≥ 10010 to 110

≥ 856 to 90

2000 ≥ 11130 to 140

≥ 11010 to 120

≥ 1028 to 110

≥ 900 to 90


FIGURE A-2 Self-generated noise levels for 1/1 octave filters with PRM831

Cont...Octave Band Analysis 1/3 Octave Linearity RangeNominal

Frequency (Hz)

High OBA Range Normal OBA RangeNominal

Frequency (Hz)

High OBA Range Normal OBA Range

PRM

831

0 dB Gain (dB)

+20 dB Gain (dB)

0 dB Gain (µdB)

+20 dB Gain (dB)

Dire

ct In

put

0 dB Gain (dB)

+20 dB Gain (µdB)

0 dB Gain (µdB)

+20 dB Gain (µdB)

2500 ≥ 11030 to 140

≥ 10812 to 120

≥ 10010 to 110

≥ 846 to 90

2500 ≥ 11031 to 140

≥ 10911 to 120

≥ 1019 to 110

≥ 891 to 90

3150 ≥ 10931 to 140

≥ 10713 to 120

≥ 9911 to 110

≥ 846 to 90

3150 ≥ 10932 to 140

≥ 10812 to 120

≥ 10010 to 110

≥ 892 to 90

4000 ≥ 10832 to 140

≥ 10614 to 120

≥ 9812 to 110

≥ 837 to 90

4000 ≥ 10833 to 140

≥ 10713 to 120

≥ 9911 to 110

≥ 883 to 90

5000 ≥ 10734 to 140

≥ 10515 to 120

≥ 9713 to 110

≥ 828 to 90

5000 ≥ 10734 to 140

≥ 10614 to 120

≥ 9812 to 110

≥ 874 to 90

6300 ≥ 10635 to 140

≥ 10416 to 120

≥ 9614 to 110

≥ 829 to 90

6300 ≥ 10635 to 140

≥ 10515 to 120

≥ 9713 to 110

≥ 865 to 90

8000 ≥ 10536 to 140

≥ 10317 to 120

≥ 9515 to 110

≥ 819 to 90

8000 ≥ 10536 to 140

≥ 10416 to 120

≥ 9614 to 110

≥ 855 to 90

10000 ≥ 10437 to 140

≥ 10218 to 120

≥ 9416 to 110

≥ 8010 to 90

10000 ≥ 10436 to 140

≥ 10317 to 120

≥ 9515 to 110

≥ 846 to 90

12500 ≥ 10338 to 140

≥ 10119 to 120

≥ 9317 to 110

≥ 7911 to 90

12500 ≥ 10337 to 140

≥ 10287 to 120

≥ 9416 to 110

≥ 837 to 90

16000 ≥ 10139 to 140

≥ 10020 to 120

≥ 9218 to 110

≥ 7812 to 90

16000 ≥ 10139 to 140

≥ 10119 to 120

≥ 9317 to 110

≥ 829 to 90

20000 ≥ 10040 to 140

≥ 9921 to 120

≥ 9119 to 110

≥ 7713 to 90

20000 ≥ 10040 to 140

≥ 10020 to 120

≥ 9218 to 110

≥ 8110 to 90

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

1 10 100 1000 10000

PRM831 1/1 OBA Noise Floor

High +0dB

High +20dB

Normal +0dB

Normal +20dB


FIGURE A-3 Self-generated noise levels for 1/1 octave filters with direct input

FIGURE A-4 Self-generated noise levels for 1/3 octave filters with PRM831

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

1 10 100 1000 10000

Direct 1/1 OBA Noise Floor

High +0dB

High +20dB

Normal +0dB

Normal +20dB

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

1 10 100 1000 10000

PRM831 1/3 OBA Noise Floor

High +0dB

High +20dB

Normal +0dB

Normal +20dB


FIGURE A-5 Self-generated noise levels for 1/3 octave filters with direct input

OBA Measurement SystemIntegration Method: Follows setting for SLMFrequency Weightings: Independent of setting forSLM, selected frequency weighting (A, C or Z)indicated by Time Weightings/Detectors: Follows setting forSLM, time weighting (S, F or I) indicated by

OBA MeasurementsInstantaneous “Live” Metrics: For display andprofile graph, not stored with measurement.

Overall Metrics:

Percentile Spectrum Levels, uses samepercentages n1 through n6 selected in SLM, 0.01 to99.99%

Statistics are sampled every 100ms from theselected OBA frequency weighting and timeweighting into 0.1 dB wide amplitude classes

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

1 10 100 1000 10000

Direct 1/3 OBA Noise Floor

High +0dB

High +20dB

Normal +0dB

Normal +20dB

Linear Exponent Units

OBA Live Equivalent Level Spectrum, 1s

Lωeq(f) LωƬeq(f) dB


OBA Overall Equivalent Level Spectrum


OBA Overall Maximum Level Spectrum

Lωmax(f) LωƬmax(f) dB

OBA Overall Minimum Level Spectrum

LƬmin(f) LωƬmin(f) dB

Units

1 LωƬn1(f) dB

2 LωƬn2(f) dB

3 LωƬn3(f) dB

4 LωƬn4(f) dB

5 LωƬn5(f) dB

6 LωƬn6(f) dB


A.4 Event Logging Software – Option 831C-ELAMeasurement HistoryTime Period: Selectable from 1 minute to 99 hours59 minutesSynchronization: Selectable to sync to time-of-day clock, for periods of 1, 2, 5, 10, 15, 20, 30minutes, and 1, 24 hoursMeasurements: Same measurements as Overallmeasurement

Event HistoryDetection Methods: Level or DynamicLevel Triggering: Events are initiated and storedwhen the measured sound level exceeds thetrigger levels SPL1 and Peak 1 for the specifiedminimum duration and ends when not triggeredfor the continuation timeDynamic Triggering: Trigger level is offset above abackground tracking levelTrigger Levels: Selectable from 0 to 200 dB for theSPL (LωƬ) or Peak (Lρpeak)Dynamic Trigger Offset: Selectable from 3 to 99.9dB for SPL (LωƬ) above background tracking levelDynamic Trigger Response: Selectable from fivecombinations of background tracking rate andtracking percentileMinimum Duration: Selectable from 0 to 9.9 sContinuation Period: Selectable from 0 to 9 sEvent Time History: Selectable On or Off

• Period: Selectable for periods 20 ms, 50 ms,100 ms, 200 ms, 500 ms, 1 s, 2 s, and 5 s

• Pre-event Samples: Selectable from 0 to 99• Post-event Samples: Selectable from 0 to

100• Maximum Samples: Selectable up to 9999 • Spectral Mode: Selectable On or Off,

enables Spectral Event Time History(requires 831C-OB3)

Event Measurements:• Date and Time of initial occurrence

• yyyy-mmm-dd hh:mm:ss• Date and Time of maximum occurrence

• yyyy-mmm-dd hh:mm:ss• Duration of event

• hh:mm:ss.s


Equivalent Level Lωeq LωƬeq dB

Sound Exposure Level

LωE LωƬE dB

Sound Exposure EωE EωƬE Pa²s

OBA Live Equivalent Level

Spectrum (requires 831C-

OB3)


OBA Live Maximum Level

Spectrum (requires 831C-

OB3)

Lωmax(f) LωƬmax(f) dB

Units

Maximum Level LωƬmax dB

Maximum Peak Level

Lρpeak dB


Event Time History Equivalent Level

Lωeq LωƬeq dB

Event Time History Equivalent Level 1/1

or 1/3 Spectra (requires 831C-OB3)



A.5 Time History Software – Option 831C-LOGTime-History Measurement SystemThe Time History can log an abundant selection ofacoustic and non-acoustic metrics at equal timeintervals.Time Period: Selectable for periods 2.5 ms, 5 ms,10 ms, 20 ms, 50 ms, 100 ms, 200 ms, 500 ms, 1 s, 2s, 5 s, 10 s, 15 s, 20 s, 30 s, 1 min, 2 min, 5 min, 10min, 15 min, 20 min, 30 min, 1 h, and 24 hSynchronization: Selectable to sync to time-of-day clock, for periods of 1, 2, 5, 10, 15, 20, 30seconds; 1, 2, 5, 10, 15, 20, 30 minutes; and 1, 24hours

Acoustic MeasurementsMetrics are individually selectable.Period < 20 ms:

• OBA 1/1 Leq*• OBA 1/3 Leq*

Period ≥ 20ms:LAeq, LCeq, LZeq, LAPeak, LCpeak,LZpeakPeriod ≥ 100 ms:

• LAeq, LCeq, LZeq, LApeak, LCpeak, LZpeak

• LAS, LAF, LAI, LCS, LCF, LCI, LZS, LZF, LZI• LASmax, LAFmax, LAImax, LCSmax, LCFmax,

LCImax, LZSmax, LZFmax, LZImax• LASmin, LAFmin, LAImin, LCSmin, LCFmin, LCImin,

LZSmin, LZFmin, LZImin• LCeq-LAeq, LAIeq-Laeq, LAFTtm5

With option 831-IH: Ltwa1, Ltwa2

Non-Acoustic MeasurementsMetrics are individually selectable.Millisecond Resolution, Period < 1 s: TmsPeriod ≥ 100 ms: Battery Voltage, External Power,Internal Temperature426A12 or PRM2103 Metrics: InternalTemperature, Internal HumiditySEN031 Metrics: Windspeed; Wind Gust Speed;Wind Direction; Temperature: Avg, Min & Max;Humidity: Avg, Min & Max; Barometric PressureSEN032 Metrics: Windspeed; Wind Gust Speed;Wind Direction*OBA processing must be available by option 831C-OB3 and enabled by OBA Bandwidth setting.

A.6 PTB Approved FirmwareIn order to be compliant with PTB requirements,the PTB firmware option and approved firmwaremust be installed on the Model 831C SLM. Whenthe option and approved firmware are installed,an indicator will be displayed on the status barindicating the PTB seal is intact. If any deviationfrom the PTB approved state is detected, theindicator will change to show that the PTB seal hasbeen broken.Parameters checked:

• 831C-PTB option must not be masked• NF30-101 option must not be enabled• PTB approved firmware must be installed• Must be using a PRM831 or PRM2103

preamp• Must be using a 377B02 microphone• Calibration must be within 1.5 dB of the

certified sensitivity• Microphone corrections must be one of the

following:• Off• FF:RI • FF:RI 2116• FF:FF 2116 • FF:90 2116

The state of these parameters as well as the PTBseal state are stored in each data file and areviewable on the summary page of exported data.

TAKE NOTE PTB approved firmware can only be installed by an authorized representative.


A.7 Fre uency ResponseThe following data was taken using the LarsonDavis Model 831 Sound Level Meter with a PRM831preamplifier at degrees increasing by 10, starting

with 0° and rotating to 250°. The frequency wasmeasured in Hertz and ranged from 200 Hz to 20Hz.

A. .1 Plane Parallel To Display Screen

FIGURE A-6 Model 831 with 3 B Microphone

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

20°60°100°140°180°

Mic at n° Mic at n°


FIGURE A-7 Model 831 with 377B02 Microphone


-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

40°80°120°160°

Mic at n°

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

10°50°90°130°170°

Mic at n°



FIGURE A-10 Directional Characteristics

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

0°30°70°110°150°

Mic at n°

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

1000 Hz




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

281.84354.81446.68562.34707.95891.251122.021412.541778.282238.722818.383548.134466.845623.417079.468912.5111220.18

Frequency (Hz)

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

266.07334.97421.7530.88668.34841.41059.251333.521678.82113.492660.733349.654216.975308.846683.448413.9510592.5413335.2116788.04

Frequency (Hz)




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

298.54375.84473.15595.66749.89944.061188.51496.241883.652371.372985.383758.374731.515956.627498.949440.6111885.0214962.3618836.49

Frequency (Hz)

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

251.19316.23398.11501.19630.96794.3310001258.931584.891995.262511.893162.283981.075011.876309.577943.281000012589.2515848.9319952.62

Frequency (Hz)


FIGURE A-15 Model 831 with 377C20 Microphone


-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

20°60°100°140°180°

Mic at n°

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

40°80°120°160°

Mic at n°




-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

10°50°90°130°170°

Mic at n°

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

0°30°70°110°150°

Mic at n°




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

281.84354.81446.68562.34707.95891.251122.021412.541778.282238.722818.383548.134466.845623.417079.468912.5111220.18

Frequency (Hz)

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

266.07334.97421.7530.88668.34841.41059.251333.521678.82113.492660.733349.654216.975308.846683.448413.9510592.5413335.2116788.04

Frequency (Hz)




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

298.54375.84473.15595.66749.89944.061188.51496.241883.652371.372985.383758.374731.515956.627498.949440.6111885.0214962.3618836.49

Frequency (Hz)

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

251.19316.23398.11501.19630.96794.3310001258.931584.891995.262511.893162.283981.075011.876309.577943.281000012589.2515848.9319952.62

Frequency (Hz)


A. .2 Perpendicular to Plane of Display Screen

FIGURE A-23 Model 831 with 3 B Microphone

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

20°340°60°300°100°260°140°220°180°

Mic at n°




-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

40°320°80°280°120°240°160°200°

Mic at n°

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

0°30°330°70°290°110°250°150°210°

Mic at n°




-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

10°350°50°310°90°270°130°230°170°190°

Mic at n°

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

2663354225316688411059133416792113266133504217530966838414105931333516788

Frequency Hz




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

2823554475627088911122141317782239281835484467562370798913112201412517783

Frequency (Hz)

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

2993764735967509441189149618842371298537584732595774999441118851496218836

Frequency (Hz)




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

251316398501631794100012591585199525123162398150126310794310000125891584919953

Frequency (Hz)

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

20°340°60°300°100°260°140°220°180°

Mic at n°




-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

40°320°80°280°120°240°160°200°

Mic at n°

-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

0°30°330°70°290°110°250°150°210°

Mic at n°




-14

-13

-12

-11

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz @

0°)

Frequency (Hz)

10°350°50°310°90°270°130°230°170°190°

Mic at n°

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

2663354225316688411059133416792113266133504217530966838414105931333516788

Frequency Hz




-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

2823554475627088911122141317782239281835484467562370798913112201412517783

Frequency (Hz)

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

2993764735967509441189149618842371298537584732595774999441118851496218836

Frequency (Hz)



A.7.3 Random IncidenceNormalized to 1 kHz at 0 degrees.

FIGURE A-39 Random Incidence

-26

-22

-18

-14

-10

-6

-2

2

0°10°

20°

30°

40°

50°

60°

70°

80°

90°

100°

110°

120°

130°

140°

150°

160°170°

180°190°

200°

210°

220°

230°

240°

250°

260°

270°

280°

290°

300°

310°

320°

330°

340°350°

251316398501631794100012591585199525123162398150126310794310000125891584919953

Frequency (Hz)

-14

-12

-10

-8

-6

-4

-2

0

2

100

1000

1000

0

Deci

bels

(dB

re 1

000

Hz)

Frequency (Hz)

Randomized


A.7.4 Typical Z-Weight Frequency Response

For frequency responses of the Model with thePRM2103 preamplifier, see the Larson Davis

PRM2103 Outdoor Microphone PreamplifierManual.

FIGURE A-40 Z Frequency Weighting, Direct Input

-30.0

-20.0

-10.0

0.0

(dB)

Z Frequ

-80.0

-70.0

-60.0

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

1E-1 1E+0 1E+1 1E+2 1E+3 1E+4 1E+5

Resp

onse

(dB)

Frequency (Hz)

Z Frequency Weighting, Direct Input


A.8 Declaration of Conformity

SoundAdvisor Model 831C B-1

Appendix B Measuring Sound Using IEC 61672-1

B.1 OverviewThis appendix presents information for assessingthe sound level meter functionality of the Larson

Davis SoundAdvisor Model 831C according to IEC61672-1 Edition 2.0 2013-09.

B.2 Section 9.3a) Reference Sound Pressure LevelThe reference sound pressure level is 114 dB re 20µPa.

b) Reference Level RangeThe reference level range is 0 dB gain (SLM) andHigh Range (OBA).

c) Microphone Reference PointThe microphone reference point is the center ofthe diaphragm of the 377B02 microphone.

d) Periodic TestingTable A.5, “SLM with PRM831 and 377B02Microphone,” on page 6-A lists values of 831C withPRM831 and 377B02 Microphone adjustment dataof A-weighted levels used for periodicmeasurements.

e) Frequency Response and CorrectionsSee Table A.5, “SLM with PRM831 and 377B02Microphone,” on page 6-A.

Table B.1 831C with PRM831 and 377B02 Microphone average frequency responses and corrections Required by IEC 61672-1

Exact Frequency

0° Free Field Response

0° Free Field Corrections1

Effect of Wind Screen

Wind Screen on 831C 0° Free Field

0° Free Field Corrections with Wind Screen on

831C¹

expanded uncertainty

of Corrections

'@ 95%

Hz dB dB dB dB dB dB

251.19 -0.03 0.03 0.03 0.00 0.00 0.25

316.23 -0.11 0.11 0.15 0.04 -0.04 0.25

398.11 0.12 -0.12 -0.03 0.09 -0.09 0.25

501.19 0.14 -0.14 0.00 0.14 -0.14 0.25

630.96 0.18 -0.18 -0.09 0.09 -0.09 0.25

794.33 0.15 -0.15 -0.07 0.08 -0.08 0.25

1000.00 0.00 0.00 0.00 0.00 0.00 0.25

1059.25 0.00 -0.00 0.11 0.11 -0.11 0.25

1122.02 -0.12 0.12 0.03 -0.09 0.09 0.25

1188.50 -0.21 0.21 0.13 -0.08 0.08 0.25

1258.93 -0.39 0.39 0.31 -0.08 0.08 0.25

1333.52 -0.29 0.29 0.21 -0.08 0.08 0.25

1412.54 -0.27 0.27 0.20 -0.07 0.07 0.25

1496.24 -0.13 0.13 0.07 -0.06 0.06 0.25


1584.89 -0.02 0.02 0.23 0.21 -0.21 0.25

1678.80 0.01 -0.01 0.24 0.25 -0.25 0.25

1778.28 -0.01 0.01 0.26 0.25 -0.25 0.25

1883.65 -0.08 0.08 0.40 0.32 -0.32 0.25

1995.26 0.20 -0.20 0.43 0.63 -0.63 0.25

2113.49 0.36 -0.36 0.40 0.76 -0.76 0.35

2238.72 0.24 -0.24 0.53 0.77 -0.77 0.35

2371.37 0.01 -0.01 0.59 0.60 -0.60 0.35

2511.89 -0.03 0.03 0.60 0.57 -0.57 0.35

2660.73 0.19 -0.19 0.42 0.61 -0.61 0.35

2818.38 0.00 -0.00 0.55 0.55 -0.55 0.35

2985.38 -0.27 0.27 0.35 0.08 -0.08 0.35

3162.28 -0.04 0.04 0.30 0.26 -0.26 0.35

3349.65 0.01 -0.01 0.11 0.12 -0.12 0.35

3548.13 -0.13 0.13 -0.01 -0.14 0.14 0.35

3758.37 0.10 -0.10 -0.00 0.10 -0.10 0.35

3981.07 0.10 -0.10 0.00 0.10 -0.10 0.35

4216.97 -0.03 0.03 -0.20 -0.23 0.23 0.45

4466.84 0.35 -0.35 -0.22 0.13 -0.13 0.45

4731.51 0.06 -0.06 -0.39 -0.33 0.33 0.45

5011.87 -0.08 0.08 -0.39 -0.47 0.47 0.45

5308.84 -0.04 0.04 0.04 0.00 0.00 0.45

5623.41 -0.02 0.02 -0.09 -0.11 0.11 0.45

5956.62 0.04 -0.04 -0.16 -0.12 0.12 0.45

6309.57 0.21 -0.21 0.14 0.35 -0.35 0.45

6683.44 0.02 -0.02 0.25 0.27 -0.27 0.45

7079.46 0.04 -0.04 0.12 0.16 -0.16 0.45

7498.94 0.01 -0.01 -0.14 -0.13 0.13 0.45

7943.28 -0.03 0.03 -0.29 -0.32 0.32 0.45

8413.95 0.27 -0.27 -0.39 -0.12 0.12 0.55

8912.51 0.06 -0.06 0.13 0.19 -0.19 0.55

9440.61 0.01 -0.01 -0.03 -0.02 0.02 0.55

10000.00 0.01 -0.01 0.21 0.22 -0.22 0.55

10592.54 0.07 -0.07 0.09 0.16 -0.16 0.55

11220.18 0.05 -0.05 -0.05 0.00 0.00 0.55



11885.02 -0.01 0.01 -0.20 -0.21 0.21 0.55

12589.25 0.23 -0.23 -0.26 -0.03 0.03 0.55

13335.21 0.24 -0.24 -0.26 -0.02 0.02 1.00

14125.38 0.08 -0.08 -0.15 -0.07 0.07 1.00

14962.36 0.05 -0.05 -0.01 0.04 -0.04 1.00

15848.93 -0.23 0.23 0.41 0.18 -0.18 1.00

16788.04 -0.20 0.20 0.14 -0.06 0.06 1.00

17782.79 -0.15 0.15 -0.08 -0.23 0.23 1.00

18836.49 -0.18 0.18 -0.41 -0.59 0.59 1.00

19952.62 -0.13 0.13 -1.33 -1.46 1.46 1.00

1. Add numbers in this column to levels read on the 831 to correct the level at a specific frequency

Table B.2 Directional Response of 3 ½-inch Windscreen

Frequency (Hz)

Angle from Reference Direction (Degrees)1

0 15 30 45 60 75 90 105 120 135 150 165 180

251.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

266.07 0.00 0.00 0.03 -0.03 0.00 0.00 0.00 -0.03 0.03 0.00 -0.03 -0.03 0.00

281.84 0.00 0.10 0.07 -0.03 -0.07 0.00 0.03 0.00 0.07 0.00 -0.03 0.03 0.00

298.54 0.07 0.07 0.00 0.00 -0.03 0.00 0.03 -0.03 -0.03 0.03 -0.10 0.03 0.00

316.23 0.00 0.03 0.07 0.00 -0.07 -0.03 0.00 -0.03 0.03 -0.03 -0.10 0.07 0.00

334.97 0.00 0.00 0.03 0.00 -0.07 -0.03 0.07 -0.13 0.00 0.00 -0.07 0.07 0.00

354.81 0.03 0.07 0.10 -0.03 -0.07 0.00 0.00 -0.03 0.03 0.03 -0.03 0.03 0.00

375.84 0.03 0.07 0.03 0.00 -0.03 -0.03 0.00 -0.03 0.03 0.00 -0.10 0.00 0.00

398.11 0.00 0.00 0.10 -0.03 -0.03 0.00 0.00 -0.03 0.07 -0.03 -0.07 0.07 0.07

421.70 0.00 0.00 0.07 0.03 -0.07 -0.03 0.00 -0.03 0.03 0.00 -0.07 0.00 0.00

446.68 0.00 0.03 0.03 -0.03 0.00 -0.03 0.10 0.03 0.03 0.00 0.00 0.00 0.00

473.15 0.03 0.03 0.03 0.00 0.03 -0.03 0.07 0.00 0.03 0.00 -0.07 0.03 0.00

501.19 0.10 0.10 0.13 0.07 -0.03 0.07 0.00 0.00 0.13 0.10 -0.07 0.03 0.00

530.88 0.03 0.10 0.13 0.07 -0.07 0.07 0.03 0.03 0.07 0.00 -0.03 0.03 0.00

562.34 0.10 0.10 0.13 0.07 0.03 0.07 0.00 -0.03 0.13 0.10 -0.03 0.00 0.07

595.66 0.07 0.10 0.13 0.07 -0.03 0.03 0.00 0.00 0.10 0.07 -0.03 0.07 0.00

630.96 0.03 0.00 0.07 -0.03 0.00 0.07 0.10 0.07 0.13 0.10 0.03 0.10 0.10

668.34 0.10 0.10 0.13 0.07 0.03 0.00 0.03 0.03 0.07 0.00 0.03 0.10 0.00

707.95 0.10 0.10 0.13 0.07 0.03 0.07 0.10 0.07 0.03 0.10 0.03 0.10 0.00

749.89 0.10 0.10 0.13 0.07 0.00 -0.03 0.10 0.07 0.13 0.10 0.03 0.10 0.10

794.33 0.10 0.10 0.13 0.07 0.03 0.13 0.10 0.07 0.13 0.10 0.03 0.10 0.10

841.40 0.03 0.07 0.10 0.07 0.03 0.07 0.10 0.10 0.03 0.10 0.03 0.10 0.10



891.25 0.10 0.07 0.10 0.00 0.03 0.07 0.03 0.07 0.13 0.07 0.03 0.10 0.10

944.06 0.13 0.17 0.20 0.07 0.07 0.07 0.13 0.17 0.20 0.17 0.03 0.17 0.13

1000.00 0.20 0.10 0.13 0.07 0.03 0.17 0.10 0.17 0.23 0.10 0.03 0.10 0.10

1059.25 0.10 0.10 0.23 0.17 0.13 0.07 0.10 0.07 0.13 0.10 0.03 0.10 0.10

1122.02 0.20 0.23 0.23 0.13 0.13 0.17 0.10 0.17 0.23 0.20 0.13 0.13 0.10

1188.50 0.20 0.10 0.23 0.07 0.13 0.17 0.10 0.17 0.13 0.20 0.13 0.17 0.10

1258.93 0.13 0.17 0.23 0.17 0.13 0.17 0.23 0.13 0.23 0.17 0.13 0.10 0.20

1333.52 0.20 0.20 0.33 0.27 0.13 0.17 0.20 0.23 0.23 0.20 0.13 0.20 0.10

1412.54 0.20 0.20 0.23 0.17 0.23 0.17 0.20 0.27 0.23 0.20 0.13 0.17 0.20

1496.24 0.23 0.20 0.23 0.17 0.23 0.17 0.20 0.27 0.23 0.27 0.13 0.10 0.20

1584.89 0.33 0.30 0.37 0.30 0.27 0.27 0.33 0.27 0.30 0.27 0.20 0.27 0.30

1678.80 0.30 0.30 0.40 0.37 0.33 0.27 0.30 0.27 0.33 0.20 0.17 0.20 0.27

1778.28 0.40 0.40 0.43 0.37 0.33 0.33 0.40 0.37 0.33 0.40 0.13 0.30 0.30

1883.65 0.40 0.40 0.43 0.37 0.33 0.37 0.40 0.37 0.33 0.30 0.23 0.30 0.30

1995.26 0.40 0.50 0.43 0.47 0.43 0.47 0.40 0.37 0.37 0.40 0.23 0.33 0.30

2113.49 0.50 0.50 0.53 0.47 0.43 0.47 0.40 0.47 0.43 0.37 0.33 0.33 0.40

2238.72 0.50 0.50 0.53 0.47 0.43 0.47 0.50 0.47 0.47 0.40 0.30 0.40 0.40

2371.37 0.50 0.50 0.53 0.47 0.43 0.47 0.50 0.47 0.53 0.50 0.33 0.50 0.40

2511.89 0.50 0.57 0.53 0.57 0.50 0.57 0.53 0.53 0.53 0.50 0.37 0.47 0.47

2660.73 0.53 0.53 0.57 0.57 0.50 0.50 0.60 0.50 0.53 0.50 0.43 0.50 0.43

2818.38 0.57 0.53 0.57 0.60 0.50 0.50 0.53 0.53 0.57 0.57 0.43 0.57 0.50

2985.38 0.40 0.50 0.43 0.57 0.43 0.50 0.57 0.53 0.57 0.57 0.37 0.50 0.50

3162.28 0.40 0.40 0.53 0.50 0.33 0.57 0.50 0.47 0.53 0.50 0.43 0.50 0.50

3349.65 0.30 0.40 0.37 0.37 0.37 0.43 0.40 0.40 0.43 0.43 0.40 0.50 0.50

3548.13 0.23 0.27 0.33 0.30 0.23 0.37 0.33 0.33 0.37 0.40 0.33 0.40 0.40

3758.37 0.20 0.23 0.13 0.17 0.23 0.27 0.20 0.23 0.33 0.37 0.27 0.40 0.30

3981.07 0.10 0.10 0.13 0.13 0.00 0.13 0.10 0.10 0.23 0.20 0.13 0.27 0.23

4216.97 0.03 0.00 0.10 0.03 -0.10 0.07 0.00 -0.03 0.07 0.03 0.03 0.10 0.13

4466.84 0.00 -0.07 -0.07 -0.07 -0.17 -0.07 -0.10 -0.10 -0.07 0.00 -0.07 0.00 0.00

4731.51 -0.30 -0.20 -0.17 -0.23 -0.27 -0.30 -0.30 -0.43 -0.27 -0.20 -0.37 -0.20 -0.20

5011.87 -0.17 -0.20 -0.17 -0.30 -0.27 -0.23 -0.40 -0.33 -0.37 -0.40 -0.37 -0.30 -0.30

5308.84 0.00 -0.10 -0.07 -0.23 -0.30 -0.33 -0.40 -0.43 -0.47 -0.50 -0.60 -0.43 -0.43

5623.41 0.00 -0.07 -0.03 -0.17 -0.20 -0.33 -0.37 -0.43 -0.47 -0.50 -0.53 -0.43 -0.43

5956.62 0.17 0.07 0.10 -0.13 -0.17 -0.23 -0.33 -0.37 -0.43 -0.50 -0.57 -0.50 -0.40

6309.57 0.10 0.20 0.23 -0.03 -0.07 -0.03 -0.10 -0.33 -0.37 -0.40 -0.47 -0.40 -0.30

6683.44 0.13 0.10 0.20 0.07 -0.03 -0.03 -0.13 -0.17 -0.27 -0.33 -0.40 -0.40 -0.20

7079.46 0.03 0.07 0.07 0.07 0.03 0.00 -0.10 -0.13 -0.17 -0.27 -0.27 -0.23 -0.13

7498.94 -0.10 -0.10 -0.07 -0.03 -0.07 -0.03 -0.20 -0.23 -0.27 -0.20 -0.27 -0.10 -0.10

7943.28 -0.30 -0.37 -0.30 -0.23 -0.33 -0.23 -0.33 -0.40 -0.37 -0.33 -0.33 -0.20 -0.17

8413.95 -0.40 -0.37 -0.37 -0.43 -0.53 -0.43 -0.57 -0.57 -0.57 -0.50 -0.43 -0.23 -0.37



FIGURE B-1 Windscreen Direction

EPS2116 Corrections

The following graph and table display correction factors for effects of the EPS2116 on the response of thesound level meter. These are corrections are intended for laboratory use when testing to IEC 61672-3 toaccount for effects of the EPS2116 when measurements are taken. See Table A.1 for the appropriate filterselection in the sound level meter for a given test as well as the associated correction factor to beapplied. Note that the correction factors are tabulated in Table A.2.

8912.51 -0.40 -0.50 -0.37 -0.53 -0.67 -0.63 -0.70 -0.73 -0.73 -0.80 -0.73 -0.50 -0.50

9440.61 -0.37 -0.40 -0.37 -0.50 -0.67 -0.70 -0.70 -0.83 -0.77 -0.90 -0.93 -0.77 -0.60

10000.00 -0.13 -0.20 -0.27 -0.43 -0.57 -0.57 -0.77 -0.83 -0.77 -0.90 -0.97 -0.90 -0.70

10592.54 -0.20 -0.20 -0.17 -0.40 -0.47 -0.47 -0.70 -0.83 -0.83 -0.83 -0.97 -0.87 -0.70

11220.18 -0.47 -0.43 -0.37 -0.43 -0.53 -0.47 -0.70 -0.90 -0.77 -0.80 -0.77 -0.90 -0.67

11885.02 -0.67 -0.73 -0.63 -0.60 -0.73 -0.57 -0.83 -0.90 -0.83 -0.87 -0.73 -0.70 -0.70

12589.25 -0.57 -0.73 -0.83 -0.87 -0.97 -0.97 -1.00 -1.00 -1.00 -1.17 -1.07 -0.90 -0.90

13335.21 -0.70 -0.67 -0.63 -0.83 -1.00 -1.17 -1.10 -1.07 -1.07 -1.37 -1.53 -1.20 -1.13

14125.38 -0.40 -0.50 -0.57 -0.60 -0.90 -1.00 -1.00 -1.20 -1.17 -1.37 -1.63 -1.47 -1.20

14962.36 -0.70 -0.73 -0.53 -0.73 -0.97 -0.90 -1.10 -1.33 -1.23 -1.50 -1.53 -1.43 -1.13

15848.93 -0.90 -0.90 -0.97 -1.03 -1.27 -1.13 -1.30 -1.60 -1.37 -1.57 -1.37 -1.40 -1.17

16788.04 -0.90 -1.07 -1.00 -1.30 -1.33 -1.47 -1.50 -1.53 -1.40 -1.70 -1.77 -1.43 -1.43

17782.79 -0.87 -0.93 -0.93 -1.10 -1.33 -1.53 -1.70 -1.57 -1.67 -1.73 -2.30 -2.00 -1.70

18836.49 -0.90 -1.10 -0.90 -1.10 -1.43 -1.43 -1.70 -1.83 -1.80 -1.83 -2.13 -2.27 -1.77

19952.62 -1.27 -1.30 -1.13 -1.47 -1.73 -1.67 -2.07 -2.30 -1.97 -2.23 -2.13 -1.97 -1.67

1. The corrections which should be subtracted from the measured data when using the Larson-Davis Model WS001 3½-inch diameter windscreen with a ½-inch Larson-Davis microphone are as indicated in the follow-ing table

Test Sound Level Meter Filter EPS 2116 Correction(See Table A.2)

Free Field Response FF:FF 2116 Free Field to Free Field EPS2116 Correction Factor



90 Degree Response FF:90 2116 Free Field to 90 Degree EPS2116 Correction Factor

Random Incidence Response

FF:RI 2116 Free Field to Random Incidence EPS 2116

Test Sound Level Meter Filter EPS 2116 Correction(See Table A.2)


Table B.3 EPS2116 Windscreen Corrections

Frequency Free Field to Free Field EPS2116 Correction Factor

Free Field to 90 Degree EPS2116 Correction Factor

Free Field to Random Incidence EPS2116 Correction Factor

Expanded Uncertainty

Hz dB dB dB dB

63.10 0.00 0.00 0.00 0.20

79.43 0.00 0.00 0.00 0.20

100.00 0.00 0.00 0.00 0.20

125.89 0.00 0.00 0.00 0.20

158.49 0.00 0.00 0.00 0.20

199.53 0.04 0.00 0.00 0.20

251.19 0.07 0.00 0.00 0.20

266.07 0.04 -0.10 -0.06 0.20

281.84 0.05 -0.04 -0.06 0.20

298.54 0.06 -0.01 -0.02 0.20

316.23 0.10 -0.02 -0.04 0.20

334.97 0.09 -0.06 -0.04 0.20

354.81 0.10 0.00 -0.01 0.20

375.84 0.08 -0.06 -0.04 0.20

398.11 0.12 -0.03 0.03 0.20

421.7 0.11 -0.02 -0.01 0.20

446.68 0.14 -0.01 0.03 0.20

473.15 0.12 -0.05 0.00 0.20

501.19 0.29 -0.01 0.06 0.20

530.88 0.35 -0.02 0.11 0.20

562.34 0.34 -0.05 0.09 0.20

595.66 0.29 -0.01 0.06 0.20

630.96 0.29 -0.01 0.07 0.20

668.34 0.31 -0.01 0.09 0.20

707.95 0.40 0.05 0.12 0.20

749.89 0.36 -0.01 0.07 0.20

794.33 0.35 0.00 0.08 0.20

841.4 0.37 -0.01 0.07 0.20


891.25 0.44 0.04 0.13 0.20

944.06 0.52 0.04 0.17 0.20

1000 0.55 0.06 0.16 0.20

1059.25 0.55 0.05 0.15 0.20

1122.02 0.70 0.13 0.17 0.20

1188.5 0.65 0.13 0.20 0.20

1258.93 0.72 0.14 0.23 0.20

1333.52 0.70 0.08 0.20 0.20

1412.54 0.70 0.08 0.20 0.20

1496.24 0.75 0.14 0.24 0.20

1584.89 0.78 0.03 0.24 0.20

1678.8 0.77 0.04 0.24 0.20

1778.28 0.79 0.04 0.23 0.20

1883.65 0.77 0.02 0.18 0.20

1995.26 0.85 0.10 0.17 0.20

2113.49 0.70 0.15 0.12 0.20

2238.72 0.75 0.20 0.08 0.20

2371.37 0.55 0.15 0.00 0.20

2511.89 0.72 0.12 -0.07 0.20

2660.73 0.74 0.14 -0.07 0.20

2818.38 0.77 -0.21 -0.20 0.20

2985.38 0.50 -0.51 -0.26 0.20

3162.28 0.55 -0.65 -0.47 0.20

3349.65 0.66 -0.69 -0.68 0.20

3548.13 0.41 -0.70 -0.79 0.20

3758.37 0.21 -1.05 -0.97 0.20

3981.07 0.30 -1.55 -1.23 0.20

4216.97 0.16 -2.05 -1.39 0.30

4466.84 -0.06 -2.54 -1.56 0.30

4731.51 0.19 -2.61 -2.00 0.30

5011.87 0.02 -2.78 -2.08 0.30

5308.84 0.20 -3.35 -2.27 0.30

5623.41 0.15 -3.58 -2.42 0.30


f) Linear Operating Range

g) Linear Measurement Starting Point

5956.62 -0.09 -3.58 -2.61 0.30

6309.57 -0.16 -3.41 -2.72 0.30

6683.44 -0.30 -3.36 -2.78 0.30

7079.46 -0.13 -3.48 -2.88 0.30

7498.94 -0.20 -3.40 -2.91 0.30

7943.28 -0.26 -3.36 -3.05 0.30

8413.95 -0.40 -3.78 -3.18 0.30

8912.51 -0.60 -3.81 -3.23 0.30

9440.61 -0.52 -4.10 -3.27 0.30

10000 -0.30 -4.42 -3.32 0.30

10592.54 -0.42 -4.45 -3.30 0.30

11220.18 -0.66 -4.49 -3.12 0.30

11885.02 -0.50 -4.31 -2.90 0.30

12589.25 -0.57 -4.41 -2.76 0.30

13335.21 -1.17 -4.64 -2.90 0.30

14125.38 -1.59 -4.95 -3.41 0.30

14962.36 -2.20 -5.41 -4.07 0.30

15848.93 -3.05 -6.30 -4.98 0.30

16788.04 -3.88 -7.46 -6.31 0.30

17782.79 -5.38 -8.87 -7.91 0.30

18836.49 -6.56 -10.06 -9.40 0.30

19952.62 -8.15 -11.24 -10.80 0.30

Table B.4 Linearity Range (Nominal Values)

Weighting Gain31.5 Hz 1 kHz 4 kHz 8 kHz 12.5 kHz

Lower Upper Lower Upper Lower Upper Lower Upper Lower Upper

A 0 dB 22.6 100.5 22.6 140 22.6 141 22.6 138.9 22.6 135.7

20 dB 18 80.5 18 120 18 121 18 118.9 18 115.7

C 0 dB 25 137.5 25 140.5 25 139.7 25 137.4 25 134.3

20 dB 24 117.4 24 120.4 24 119.6 24 117.4 24 114.2

Z 0 dB 36 140.5 36 140.5 36 140.5 36 140.5 36 140.5

20 dB 35 120.5 35 120.5 35 120.5 35 120.5 35 120.5


h) Electrical Insert SignalsThe electrical design of the input device to insert electrical signals into the preamplifier is a series 12pF ±5% capacitor. The Larson Davis ADP090 is used for this purpose. The ADP090 is also use for noise floormeasurements by attaching the included BNC short on the front of the ADP090.

i) Self Generating Noise in Low Level Sound Field

j) Highest Sound Pressure LevelThe highest sound pressure level the Larson Davis 831C is designed to accommodate at the level ofoverload is 140 dB. The maximum peak-to-peak voltage is 28 Vpp input through the ADP090.

k) Battery Power Voltage RangeThe battery power supply voltage range for which the 831C conforms to this standard:16.8 Volts maximumThe 831C will shut down if the battery is below 4.0 Volts when used with alkaline batteries. Thereforefrom 4.0 to 16.8 Volts is the usable range of battery voltage. The instrument will shut off to ensure thatno data is taken that would not meet the requirements of IEC 61672.

l) Typical Stabilization TimeThe typical time interval needed to stabilize after changes in environmental conditions:For a temperature change of 5 °C then 30 minutes are required.For a static pressure change of 5 kPa then 15 seconds are required.For a humidity change of 25% (non-condensing) then 30 minutes are required.

Table B.5 Linear Measurement Starting Point

Gain 31.5 Hz 1 kHz 4 kHz 8 kHz 12.5 kHz

0 dB 74.5 dB 114 dB 115 dB 112.9 dB 109.7 dB

20 dB 54.5 dB 94dB 95 dB 92.9 dB 89.7 dB

Table B.6 SLM Noise Levels

Self Generated Electrical Noise 0 dB Gain 20 dB Gain

Weighting Typical (dB) Max (dB) Typical (dB) Max (dB)

A 10 12 6 9

C 13 16 12 15

Z 22 25 22 25

Self Generated Total Noise 0 dB Gain 20 dB Gain

Weighting Typical (dB) Max (dB) Typical (dB) Max (dB)

A 16 19 16 17

C 17 20 16 19

Z 23 26 23 26

Note: Combination of the electronic noise and the thermal noise of the 377B02 microphone at 68 °F (20 °C) measured in a sealed and vibration isolated cav-ity with an averaging time of 60 seconds. Electronic noise of the instrument with an ADP090 (12 pF) in place of the microphone highest anticipated self-generated noise.


m) Field Strength 1 /mThe 831C was not measured for field strengths greater than 10 V/m.

n) Radio Fre uency EmissionThe mode of operation of the 831C that produces the greatest radio frequency emission levels is with the831C set to run with the LCD backlights on, an external charger (PSAA20R-120 charger), Ethernet dongle,and USB cable attached and with an E C020 (20 microphone extension cable) between the PRM831 andmeter.

o) AC Power and Radio Fre uency SusceptibilityThe mode of operation of the 831C that produced the least immunity to the effects of exposure to ACpower-frequency and radio frequency field is with the 831C set to run with the LCD backlights on, anexternal charger (PSAA20R-120 charger), Ethernet dongle, and USB cable attached and with an E C020(20 microphone extension cable) between the PRM831 and meter.

FIGURE B-2 EM Field Orientation

EM Field Principal Direction

SoundAdvisor Model 831C C-1

Appendix C GlossaryC.1 OverviewThis appendix contains technical definitions of key acoustical and vibration terms commonly used with Larson Davis instru-ments. The reader is referred to American National Standards Institute document S1.1-1994 (R2004) for additional definitions.Specific use of the terms defined are in the main body of the text.

C.2 Glossary of Terms

Allowed Exposure Time (Ti)

The allowed time of exposure to sound that a constant A-weighted sound level in achosen Criterion Level, Criterion Duration, and Exchange Rate.

The equation for Ti is

where Lc is the Criterion Level, Tc is the Criterion Duration, Q is the Exchange Rate, q isthe Exchange Rate Factor and Lavg is the Average Sound Level.

Example: If Lc = 90, Tc = 8, Q = 3 and Lavg= 95 then

This means that if a person is in this area for 2 hours and 31 minutes he will have accu-mulated a Noise Dose of 100%.

Standard: ANSI S12.19.

See "Exchange Rate (Q), Exchange Rate Factor (q), Exposure Factor (k)"

At Lmax

At Lmax is one of 2 choices for the Max Spec setting on the OBA Page of the SetupManager. See also "Bin Max"

At Lmax, is the instantaneous spectrum at the moment when thebroadband maximum occurred, such as LASmax.

Average Sound Level (Lavg)

The logarithmic average of the sound during a Measurement Duration (specific timeperiod), using the chosen Exchange Rate Factor. Exposure to this sound level over theperiod would result in the same noise dose and the actual (unsteady) sound levels. Ifthe Measurement Duration is the same as the Criterion Duration, then Lavg=LTWA(LC)where the Measurement Duration (specified time period) is T=T2-T1 and q is theExchange Rate Factor. Only sound levels above the Threshold Level are included inthe integral. Standard: ANSI S12.19

TiTc

Lavg Lc– Q2-----------------------------------------

TcLavg Lc– q

10-------------------------------------------= =

Ti8

2 95 90– 3--------------------------------- 8

10 95 90– 10--------------------------------------- 2.52 = 2 hours and 31 minutes= = =


Bin Max

Bin Max is one of 2 choices for the Max Spec setting on the OBA Page of the Setup Manager. Seealso "At Lmax"

Bin Max is the maximum value that occurred during the entire measurement for that frequencyband. Since individual frequency bands may reach their maximum levels at different times, thisspectrum might be one which never occurred at any instant during the measurement period.

Community Noise Equivalent Level (CNEL, Lden)

A rating of community noise exposure to all sources of sound that differentiates between daytime,evening and nighttime noise exposure. The equation for it is

The continuous equivalent sound level is generally calculated on an hourly basis and is shown inthe equation as L. The levels for the hourly periods from midnight to 7 a.m. have 10 added to themto represent less tolerance for noise during sleeping hours. The same occurs from 10 p.m. to mid-night. The levels for the hourly periods between 7 p.m. and 10 p.m. have 5 added to them to repre-sent a lessened tolerance for noise during evening activities. They are energy summed andconverted to an average noise exposure rating.

Criterion Duration (Tc)

It is the time required for a constant sound level equal to the Criterion Level to produce a NoiseDose of 100%. Criterion Duration is typically 8 hours.

Example: If the Criterion Level = 90 dB and the Criterion Duration is 8 hours, then a sound level of90 dB for 8 hours, will produce a 100% Noise Dose. See Noise Dose. Standard: ANSI S12.19

Criterion Sound Exposure (CSE)

The product of the Criterion Duration and the mean square sound pressure associated with theCriterion Sound Level when adjusted for the Exchange Rate. It is expressed in Pascals-squaredseconds when the exchange rate is 3 dB, where q is the Exchange Rate Factor. See "ExchangeRate (Q), Exchange Rate Factor (q), Exposure Factor (k)".

Standard: ANSI S1.25

Criterion Sound Level (Lc)

It is the sound level which if continually applied for the Criterion Duration will produce a NoiseDose of 100%. The current OSHA Criterion Level is 90 dB.


Lavg qLog101T--- 10

Lp t q

T1

T2

dt

=

Lden 10log10

124------ 10

Li 10+ 10

0000

0700

10Li 10

0700

1900

10Li 5+ 10

1900

2200

10Li 10+ 10

2200

2400

+ + +

=

CSE Tc10Lc q

=


Daily Personal Noise Exposure (LEP,d)

It is the level of a constant sound over the Criterion Duration that contains the same sound energyas the actual, unsteady sound over a specific period. The period is generally shorter, so the soundenergy is spread out over the Criterion Duration period.

Example: If the Criterion Duration = 8 hours and the specific period is 4 hours and the averagelevel during the 4 hours is 86 dB, then the LEP,d = 83 dB.

Day-Night Average Sound Level (DNL, Ldn)

A rating of community noise exposure to all sources of sound that differentiates between daytimeand nighttime noise exposure. The equation for it is

The continuous equivalent sound level (See definition) is generally calculated on an hourly basisand is shown in the equation as L.

The values for the hourly periods from midnight to 7 a.m. have 10 added to them to represent lesstolerance for noise during sleeping hours. The same occurs from 10 p.m. to midnight. They areenergy summed and converted to an average noise exposure rating.

Decibel (dB)

A logarithmic form of any measured physical quantity and commonly used in the measurement ofsound and vibration. Whenever the word level is used, this logarithmic form is implied. The deci-bel provides us with the possibility of representing a large span of signal levels in a simple manneras opposed to using the basic unit Pascal for acoustic measurements.

It is not possible to directly add or subtract physical quantities when expressed in decibel formsince the addition of logarithmic values correspond to multiplication of the original quantity.

The word level is normally attached to a physical quantity when expressed in decibels; for exam-ple, Lp represents the sound pressure level.

The difference between the sound pressure for silence versus loud sounds is a factor of1,000,000:1 or more, and it is very unpractical to use these large numbers. Therefore, a measurethat would relate to “the number of zeros” would help, for example, 100,000 would be equal to 50and 1000 would be equal to 30 and so on. This is the basic principal of the dB measure.

All dB values are unit free and therefore, the dB value is not the value of the quantity itself, but theratio of that quantity to an actual reference quantity used. Thus, for every level in decibels theremust be a well defined reference quantity. Sound versus vibration uses different references, butthe dB principal is the same. When the quantity equals the reference quantity the level is zero. Tokeep dB values above zero, the reference is generally set to be the lowest value of the quantitythat we can imagine or normally wish to use. Before explaining the calculation of dB values, it isuseful to remember the following rules of thumb when dB values are used for sound levels:

• Doubling of the Sound Pressure = 6 dB

• Doubling of the Sound Power = 3 dB

Ldn 10Log10

124------ 10

Li 10+ 10

0000

0700

10Li 10

0700

2200

10Li 10+ 10

2200

2400

+ +

=


• Doubling of the Perceived Sound Level = (approx) 10 dB

Note: The latter is frequency and level dependent, but the value “10 dB” is a good rule of thumb,especially around 1 kHz.

Table C.1 shows the actual value of a specific item, such as sound power, for which the sound levelis calculated. First, the sound power value is divided with the reference used and then the ten-based logarithm is applied. This value is then multiplied by 10 to create the decibel value (seeequation below).

For every 10 decibels, a unit called Bel is created. The decibel stands for: deci for “one tenth” andbel for “Bel” (compare decimeter). The relationship between Bel and decibel is thus: 1 Bel = 10decibels. It is not possible to directly add or subtract decibel values, since addition of logarithmicvalues correspond to multiplication of the original quantity.

Each time the sound pressure level increases by 6 dB, the corresponding sound pressure value isdoubled and thus multiplied by 2. Each time the sound power level increases by 3 dB, the soundpower value is multiplied by 2. Thus, it is important to notice that a doubling of the sound poweris equal to 3 dB, and a doubling of the sound pressure is equal to 6 dB, since a doubling of thesound pressure will result in a quadruple increase of the sound power. The advantage with usingdB is simply that they remain the same even if we use sound pressure or sound power. Comparethis to the use of voltage and power units in electrical engineering, units being related by P~V2. Intable 2 an illustration is made of values calculated on sound pressure, non-squared units.

The original definition of decibel was intended for power-like quantities, such as sound power. Ifwe consider sound pressure levels instead (usually denoted P in acoustics), the equation will bethe same, since the “two” in the squared units will move from within the bracket and become a 20log instead of a 10 log and thus compensate for using linear or quadratic units. Please note that itis not allowed to use 20 log for squared units, since that expression assumes that we use linearunits, like sound pressure in acoustics or voltage in electrical engineering. This is illustrated inequation below:

Table C.1 illustrates how a a tenfold increase of the sound pressure will result in an increase in 20dB steps, while sound power increases in 10 dB steps. See the linear form (Table C.1) and comparewith equation above. In conclusion, dB values are always the same, independent of using soundpower or sound pressure as the base unit. A 6 dB increase implies four times the sound power ortwo times the sound pressure.

Table C.1 Sound Level

Power form, squared units Level form

Ration of Value to Reference

Exponential Form of Ratio 10•Exponent

1 100 0

10 101 10

100 102 20

200 102.3 23

1,000 103 30

10,000 104 40

100,000 105 50

1000,000 106 60

dB 10Log10P2

P02

-------- 20Log PP0------= = p; 0 20Pa=


Department of Defense Level (LDOD)

The Average Sound Level calculated in accordance with Department of Defense Exchange Rateand Threshold Level. See "Average Sound Level (Lavg)".

Dose

See "Noise Dose (D)".

Detector

The detector converts the actual fluctuating sound from the microphone into a signal that indi-cates its amplitude. Your choice for the Detector setting (Slow, Fast, or Impulse) determines theamplitude change rate. The detector first squares the sound signal, then averages it in accordancewith the time-weighting characteristic, and then takes the square root. This results in an ampli-tude described as rms (root-mean-square).

The Slow and Fast detector responses were originally developed to slow down the movement ofthe needle on an electro-mechanical meter, so that the amplitude could be determined. Slow andFast detector settings are still useful in modern sound measurement instruments. Slow has a timeconstant of 1 second. Fast has a time constant of 1/8th second. The Impulse setting is a non-lineardetector with the rise controlled by a 35 ms time constant followed by a peak hold that has adecay rate of 2.9 dB/second.

Eight Hour Time-Weighted Average Sound Level (L TWA(8))

It is the constant sound level that would expose a person to the same Noise Dose as the actual(unsteady) sound levels. According to the ANSI S12.19 standard, the equation for it is

NOTE: This definition applies only for a Criterion Duration of 8 hours.

Table C.2 Sound Power Increase

Linear form, non-squared units Level form

Ration of Value to Reference

Exponential Form of Ratio 20•Exponent

1 100 0

10 101 20

100 102 40

200 102.3 46

1,000 103 60

10,000 104 80

100,000 105 100

1000,000 106 120

LTWA 8 Lc qLog10D

100--------- +=


Energy Equivalent Sound Level (Leq)

The level of a constant sound over a specific time period that has the same sound energy as theactual (unsteady) sound over the same period.

where p is the sound pressure and the Measurement Duration (specific time period) T=T2-T1. See “Sound Pressure Level (SPL, Lp)” on page C-13.

Exchange Rate (Q), Exchange Rate Factor (q), Exposure Factor (k)

It is defined in ANSI S1.25 as “the change in sound level corresponding to a doubling or halving ofthe duration of a sound level while a constant percentage of criterion exposure is maintained.”The rate and the factors are given in the table below.


Exponential Integration

One of 2 integration methods used on the 831C SLM.

Exponential integration shows a long decay of energy after an impulse. However, it may hidesmall events or loud impulsive events. For this reason, this method is not as commonly used as "Linear Integration". Please note that when performing time history measurements of 10 ms orless, you must use Linear integration.

You can locate this setting by selecting any menu Setup Manager General.

Far Field

There are two types of far fields: the acoustic far field and the geometric far field.

Acoustic Far Field: The distance from a source of sound is greater than an acoustic wavelength. Inthe far field, the effect of the type of sound source is negligible. Since the wavelength varies withfrequency (See the definition of Wavelength), the distance will vary with frequency. To be in thefar field for all frequencies measured, the lowest frequency should be chosen for determining thedistance. For example, if the lowest frequency is 20 Hz, the wavelength at normal temperatures isnear 56 ft. (17 m); at 1000 Hz, the wavelength is near 1.1 ft. (1/3 m). "Acoustic Near Field:" for theadvantages of being in the acoustic far field.

Geometric Far Field: The distance from a source of sound is greater than the largest dimension ofthe sound source. In the far field, the effect of source geometry is negligible. Sound sources oftenhave a variety of specific sources within them, such as exhaust and intake noise. When in the farfield, the sources have all merged into one, so that measurements made even further away will beno different. "Geometric Near Field:" for the advantages of being in the geometric far field.

Leq 10Log10

p2 t tdT1

T2po

2T--------------------------=

Table C.3 Exchange Rate

Exchange Rate, Q

Exchange Rate Factor, q

Exposure Factor, k

3.01 10 1

4 13.29 .75

5 16.61 .60

6.02 20 .50


Free Field

A sound field that is free of reflections. This does not mean that the sound is all coming from onedirection as is often assumed, since the source of sound may be spatially extensive. See the defini-tions of near and far fields for more detail. This definition is often used in conjunction with rever-berant field.

Frequency (Hz, rad/sec)

The rate at which an oscillating signal completes a complete cycle by returning to the originalvalue. It can be expressed in cycles per second and the value has the unit symbol Hz (Hertz) addedand the letter f is used for a universal descriptor. It can also be expressed in radians per second,which has no symbol, and the Greek letter w is used for a universal descriptor. The two expres-sions are related through the expression =2Pf.

Frequency Band Pass Filter

The part of certain sound level meters that divides the frequency spectrum on the sound or vibra-tion into a part that is unchanged and a part that is filtered out. It can be composed of one ormore of the following types:

Low Pass: A frequency filter that permits signals to pass through that have frequencies below acertain fixed frequency, called a cutoff frequency. It is used to discriminate against higher fre-quencies.

High Pass: A frequency filter that permits signals to pass through that have frequencies above acertain fixed frequency, called a cutoff frequency. It is used to discriminate against lower frequen-cies.

Bandpass: A frequency filter that permits signals to pass through that have frequencies above acertain fixed frequency, called a lower cutoff frequency, and below a certain fixed frequency,called an upper cutoff frequency. The difference between the two cutoff frequencies is called thebandwidth. It is used to discriminate against both lower and higher frequencies so it passes only aband of frequencies.

Octave band: A bandpass frequency filter that permits signals to pass through that have a band-width based on octaves. An octave is a doubling of frequency so the upper cutoff frequency istwice the lower cutoff frequency. This filter is often further subdivided in 1/3 and 1/12 octaves (3and 12 bands per octave) for finer frequency resolution. Instruments with these filters have a suf-ficient number of them to cover the usual range of frequencies encountered in sound and vibra-tion measurements.The frequency chosen to describe the band is that of the center frequency.Note table in Frequency Filter - Frequency Weighting.

Frequency Filter - Weighted

A special frequency filter that adjusts the amplitude of all parts of the frequency spectrum of thesound or vibration unlike band pass filters. It can be composed of one or more of the followingtypes:

A-Weighting: A filter that adjusts the levels of a frequency spectrum in the same way the humanear does when exposed to low levels of sound. This weighting is most often used for evaluation ofenvironmental sounds. See table below.

B-Weighting: A filter that adjusts the levels of a frequency spectrum in the same way the humanear does when exposed to higher levels of sound. This weighting is seldom used. See table below.

C-Weighting: A filter that adjusts the levels of a frequency spectrum in the same way the humanear does when exposed to high levels of sound. This weighting is most often used for evaluation ofequipment sounds. See table below.


Flat-Weighting: A filter that does not adjust the levels of a frequency spectrum. It is sometimes analternative selection for the frequency-weighting selection.

Z-Weighting: Similar to a flat-weighting curve, this is a bandpass filter with a passband from 10 Hzto 20 kHz.

Integration Method

See "Linear Integration", or "Exponential Integration".

Table C.4 Frequency Filter Response

Center Frequencies, Hz

Weighting Network Frequency Response

1/3 Octave 1 Octave A B C

20 -50.4 -24.2 -6.2

25 -44.7 -20.4 -4.4

31.5 31.5 -39.4 -17.1 -3.0

40 -34.6 -14.2 -2.0

50 -30.2 -11.6 -1.3

63 63 -26.2 -9.3 -0.8

80 -22.5 -7.4 -0.5

100 -19.1 -5.6 -0.3

125 125 -16.1 -4.2 -0.2

160 -13.4 -3.0 -0.1

200 -10.9 -2.0 0

250 250 -8.6 -1.3 0

315 -6.6 -0.8 0

400 -4.8 -0.5 0

500 500 -3.2 -0.3 0

630 -1.9 -0.1 0

800 -0.8 0 0

1000 1000 0 0 0

1250 0.6 0 0

1600 1.0 0 -0.1

2000 2000 1.2 -0.1 -0.2

2500 1.3 -0.2 -0.3

3150 1.2 -0.4 -0.5

4000 4000 1.0 -0.7 -0.8

5000 0.5 -1.2 -1.3

6300 -0.1 -1.9 -2.0

8000 8000 -1.1 -2.9 -3.0

10000 -2.5 -4.3 -4.4

12500 -4.3 -6.1 -6.2

16000 16000 -6.6 -8.4 -8.5

20000 -9.3 -11.1 -11.2


Leq

See “Energy Equivalent Sound Level (Leq)”, “Sound”, and “Time Weighting”

Level (dB)

A descriptor of a measured physical quantity, typically used in sound and vibration measure-ments. It is attached to the name of the physical quantity to denote that it is a logarithmic mea-sure of the quantity and not the quantity itself. The word decibel is often added after the numberto express the same thing. When frequency weighting is used the annotation is often expressed asdB(A) or dB(B).

Linear Integration

One of 2 integration methods used on the 831C SLM.

This is the default and most commonly used integration method for measuring sound. Linear inte-grates only the energy during a given period. It does not show a decay slope of a Fast, Slow, orImpulse exponential detector. For additional information, see "Exponential Integration".

You can locate this setting by selecting any menu Setup Manager General.

Ln Value

The Ln value is the sound level that has exceeded n% over the total measurement time. For exam-ple, if n=90%, a displayed value of 35dB for L90 means that for 90% of the measurement periodthe dB level was at or above 35dB. These statistical values are commonly used to describe thecharacteristics of non-steady sound such as environmental noise.

To calculate Ln values, the 831C creates an amplitude distribution table over the range 0 to 200dB, in amplitude increments of 0.1 dB. This data permits the calculation of Ln values for any valueof n in the range 00.01 to 99.99%.

Locate the Ln values on the 831C by going to Setup Manager Ln Page.

Measurement Duration (T)

The time period of measurement. It applies to hearing damage risk and is generally expressed inhours.


Microphone Guidelines

Microphone - Types: A device for detecting the presence of sound. Most often it converts thechanging pressure associated with sound into an electrical voltage that duplicates the changes. Itcan be composed of one of the following types:

Capacitor (Condenser): A microphone that uses the motion of a thin diaphragm caused by thesound to change the capacitance of an electrical circuit and thereby to create a signal. For highsensitivity, this device has a voltage applied across the diaphragm from an internal source.

Electret: A microphone that uses the motion of a thin diaphragm caused by the sound to changethe capacitance of an electrical circuit and thereby to create a signal. The voltage across the dia-phragm is caused by the charge embedded in the electret material so no internal source isneeded.

Microphone - Uses: The frequency response of microphones can be adjusted to be used in spe-cific applications. Among those used are:


Frontal incidence (Free Field): The microphone has been adjusted to have an essentially flat fre-quency response when in a space relatively free of reflections and when pointed at the source ofthe sound.

Random incidence: The microphone has been adjusted to have an essentially flat frequencyresponse for sound waves impinging on the microphone from all directions.

Pressure: The microphone has not been adjusted to have an essentially flat frequency responsefor sound waves impinging on the microphone from all directions.

What a microphone measures: A microphone detects more than just sound. The motion of amicrophone diaphragm is in response to a force acting on it. The force can be caused by a numberof sources only one of which are we interested: sound. Non-sound forces are: (1) direct physicalcontact such as that with a finger or a raindrop; (2) those caused by the movement of air over thediaphragm such as environmental wind or blowing; (3) those caused by vibration of the micro-phone housing; and (4) those caused by strong electrostatic fields.

Rules:

1. Do not permit any solid or liquid to touch the microphone diaphragm. Keep a protective gridover the diaphragm.

2. Do not blow on a microphone and use a wind screen over the microphone to reduce the effectof wind noise.

3. Mount microphones so their body is not subject to vibration, particularly in direction at rightangles to the plane of the diaphragm.

4. Keep microphones away from strong electrical fields.

A microphone measures forces not pressures. We would like the microphone to measure soundpressure (force per unit area) instead of sound force. If the pressure is applied uniformly over themicrophone diaphragm a simple constant (the diaphragm area) relates the two, but if the pres-sure varies across the diaphragm the relationship is more complex. For example, if a negativepressure is applied on one-half the diaphragm and an equal positive pressure is applied to theother half, the net force is zero and essentially no motion of the diaphragm occurs. This occurs athigh frequencies and for specific orientations of the microphone.

Rules:

1. Do not use a microphone at frequencies higher than specified by the manufacturer; to increasethe frequency response choose smaller microphones.

2. Choose a microphone for free field or random incidence to minimize the influence of orienta-tion.

A microphone influences the sound being measured. The microphone measures very small forces,low level sound can run about one-billionth of a PSI! Every measurement instrument changes thething being measured, and for very small forces that effect can be significant. When soundimpinges directly on a microphone the incident wave must be reflected since it cannot passthrough the microphone. This results in the extra force required to reflect the sound and a micro-phone output that is higher than would exist if the microphone were not there. This is moreimportant at high frequencies and when the microphone is facing the sound source.

Rules:

1. Do not use a microphone at frequencies higher than specified by the manufacturer; to increasethe frequency response choose smaller microphones.

2. Choose a microphone for free field or random incidence to minimize the influence of orienta-tion.


A microphone measures what is there from any direction: Most measurements are intended tomeasure the sound level of a specific source, but most microphones are not directional so theymeasure whatever is there, regardless of source.

Rules:

1. When making hand-held measurements, keep your body at right angles to the direction of thesound you are interested in and hold the meter as far from your body as possible. Use a tripodwhenever possible.

2. Measure the influence of other sources by measuring the background sound level without thesource of interest. You may have to correct for the background.

Near Field

There are two types of near fields: the acoustic near field and the geometric near field.

Acoustic Near Field: The distance from a source of sound is less than an acoustic wavelength. In the near field, theeffect of the type of sound source is significant. Since the wavelength varies with frequency (Seethe definition of Wavelength), the distance will vary with frequency. The most common exampleof a near field is driving an automobile with an open window. As you move your ear to the plane ofthe window, the sound pressure level builds up rapidly (wind noise) since most of the pressurechanges are to move the air and very little of it compresses the air to create sound. Persons not farway, can hardly hear what you hear. The acoustic near field is characterized by pressures that donot create sound that can be measured in the far field. Therefore measurements made here arenot useful in predicting the sound levels far way or the sound power of the source.

Geometric Near Field: The distance from a source of sound is less than the largest dimension of the sound source. In thenear field, effect of source geometry is significant. Sound sources often have a variety of specificsources within them, such as exhaust and intake noise. When in the near field, the sound of aweaker, but close, source can be louder than that of a more distant, but stronger, source. There-fore measurements made here can be used to separate the various sources of sound, but are notuseful in predicting the sound levels and sound spectrum far from the source.

Noise

Typically it is unwanted sound. This word adds the response of humans to the physical phenome-non of sound. The descriptor should be used only when negative effects on people are known tooccur. Unfortunately, this word is used also to describe sounds with no tonal content (random):

Ambient: The all encompassing sound at a given location caused by all sources of sound. It is gen-erally random, but need not be.

Background: The all encompassing sound at a given location caused by all sources of sound, butthe source to be measured. It is essentially the sound that interferes with a measurement.

Pink: It is a random sound that maintains constant energy per octave. Pink light is similar to pinknoise in that it has a higher level at the lower frequencies (red end of the spectrum).

White: It is a random sound that contains equal energy at each frequency. In this respect, it is sim-ilar to white light.

Noise Dose (D)

It is the percentage of time a person is exposed to noise that is potentially damaging to hearing.Zero represents no exposure and 100 or more represents complete exposure. It is calculated bydividing the actual time of exposure by the allowed time of exposure. The allowed time of expo-sure is determined by the Criterion Duration and by the sound level (the higher the level, the


shorter the allowed time). The sound levels must be measured with A-frequency weighting andslow exponential time weighting. See “Projected Noise Dose” on page C-12.

where T is Measurement Duration, Tc is Criteria Time, Li is TWA, Lc is Criteria Level, q is exchangerate factor; "Exchange Rate (Q), Exchange Rate Factor (q), Exposure Factor (k)"


Noise Exposure

See “Noise” on page C-11.

OSHA Level (LOSHA)

The Average Sound Level calculated in accordance with the Occupational Safety and HealthAdministration Exchange Rate and Threshold Level.

Preamplifier

A preamplifier is a part of a sound level meter that matches a particular model of microphone tothe meter. It must be chosen in conjunction with a microphone and a cable that connects them.

Projected Noise Dose

Projected Noise Dose is the Noise Dose expected if the current rate of noise exposure continuesfor the full Criterion Duration period.

Single Event Noise Exposure Level (SENEL, LAX)

The Single Event Noise Exposure Level is the total sound energy over a specific period. It is a spe-cial form of the Sound Exposure Level where the time period is defined as the start and endtimes of a noise event such as the passing of an aircraft or automobile.

Sound

Sound is comprised of rapid oscillatory compression changes in a solid, liquid, or gas mediumthat propagate to distant points. It is characterized by changes in density, pressure, motion, andtemperature. Not all rapid changes in the medium are sound since they do not propagate. Windnoise is an example of this. Sound can also be characterized as the auditory sensation evoked bythe oscillatory changes.

Sound is the physical phenomenon associated with acoustic (small) pressure waves. Noise isunwanted sound that causes adverse effects in those exposed to it, such as hearing loss or annoy-ance. It can also be defined as the sound made by other people. In every case, choosing the wordnoise involves a judgment of whether the sound is welcome or not.

Sound Exposure (E)

Sound Exposure is the total sound energy of the actual soundduring a specific time period. It is expressed in Pascals-squared seconds, or Pascals-squared hours. The following for-mula describes exposure in terms of E, where pA is the soundpressure and T2 - T1 is the Measurement Duration (specifictime period).

D 100TTc

------------10Li Lc– q

=

E t d tP ( )A2

1

2

T

T


Sound Exposure Level (SEL, LE)

The total sound energy in a specific time period usually expressed in decibels. The followingequation shows that the sound pressure is squared and integrated over a specific period of time(T2-T1).

This is called the sound exposure. It’s usually expressed in Pascals squared-seconds or Pascalssquared-hours. P0 is the reference pressure of 20 µPa and T is the reference time of 1 second. It isthen put into logarithmic form. It’s important to note that this is not an average since the refer-ence time is not the same as the integration time.

Sound Pressure

Sound Pressure is the physical characteristic of sound that can be detected by microphones. Notall pressure signals detected by a microphone are sound (e.g., wind noise).

Sound Pressure is the amplitude of the oscillating sound pressure and is measured in Pascals (Pa),or Newtons per square meter, which is a metric equivalent of pounds per square inch. To measuresound, a sound level meter uses a detector to separate the oscillating pressure from the steady(barometric) pressure. The sound level meter then squares the pressure, takes the time average,and takes the square root (this is called rms for root-mean square). This method is one of severalways to mathematically measure sound.

Moving Average: The averaging process is continually accepting new data so it is similar to anexponential moving average. In the equation, the sound pressure is squared and multiplied by aexponential decay factor, so that when the time of integration is near the current time (t) it isessentially undiminished.

For times older (less) than the current time, the value is diminished and so becomes less import-ant. The rate at which older data are made less influential is expressed by the constant T. Thelarger it is, the slower the decay factor reduces and the slower the response of the system to rapidchanges. These are standardized into 3 values called Time Weighting. See the values below.

Fixed Average: The averaging process is over a fixed time period. The equation for it is

The sound pressure is squared and averaged over a fixed time period. Unlike the moving average,the sound pressures in all time intervals are equally weighted.

Sound Pressure Level (SPL, Lp)

The logarithmic form of sound pressure. It is also expressed by attachment of the word decibel tothe number. The logarithm is taken of the ratio of the actual sound pressure to a reference sound

SEL 10Log10

p2 t tdT1

T2

p02T

-----------------------------=

prms1T--- p2 e t – T– d

ts

t

=

prms1

T2 T1– ----------------------- p2 t td

T1

T2

=


pressure which is 20 Micro-pascals ( Pa). There are various descriptors attached to this leveldepending on how the actual sound pressure is processed in the meter:

Instantaneous: The time varying reading on a meter face on in a meter output due to changes inthe sound pressure. The reading will depend on the time-weighting applied.

The fundamental relationship between the two is logarithmic

where p0 is the reference sound pressure of 20 µPa. The square of the sound pressure is a power-like quantity that can be expressed in the original form of the level definition

Sound Pressure Level can be converted to sound pressure as follows. If the sound pressure is 1Pascal, then the sound pressure level is

Calibrators often use a level of 94 dB so they generate a sound pressure of 1 Pascal.

If the sound pressure level = 76.3 dB, then the sound pressure is

Energy Average (Leq): The value of a steady sound measured over a fixed time period that has thesame sound energy as the actual time varying sound over the same period. This descriptor iswidely used. It is a fixed average. See “Sound Pressure” on page C-13.

Impulse: The value of an impulsive sound. The reading will depend on the time-weightingapplied.

Unweighted Peak: The peak value of a sound with a meter that has flat frequency weighting anda peak detector.

Weighted Peak: The peak value of a sound with a meter that has a frequency weighting otherthan flat and a peak detector.

Sound Power (W)

The sound power emitted by a sound source. It is measured in Watts.

Sound Power Level (PWL, Lw)

The logarithmic form of sound power. It is also expressed by attachment of the word decibel tothe number. The logarithm is taken of the ratio of the actual sound power to a reference soundpower, which is 1 pico-watt. Sound power level cannot be measured directly, but can only bededuced through measurements of sound intensity or sound pressure around the source. Theequation for it is

Lp 20log10prms

p0------------= prms p010

Lp 20=

Lp 10log10prms

2

p02

------------= prms2 p0

210Lp 10

=

Lp 20log101

20 10 6–---------------------- 20log10 50000 20 4.699 94.0dB= = ==

Pa 20 10 6– 1076.3 20 20 103.815 6– 20 10 2.185– 20 0.0065 0.13= = = = =

Lw 10log10W

W0--------= W W010

Lw 10=


Sound Speed

The speed at which sound waves propagate. It is measured in meters per second. It should not beconfused with sound or particle velocity which relates to the physical motion of the medium itself.

Spectrum (Frequency Spectrum)

The amplitude of sound or vibration at various frequencies. It is given by a set of numbers thatdescribe the amplitude at each frequency or band of frequencies. It is often prefixed with adescriptor that identifies it such as sound pressure spectrum. It is generally expressed as a spec-trum level.

Taktmaximal-5

An integration of the five second maximum A frequency weighted, fast time weighted sound pres-sure levels.

Where:

LAmax 5s(n) is the maximum A-weighted fast exponential time weighted sound pressure level foreach n 5-second time period and n is the number of 5 second periods accumulated during themeasurement.

Threshold Sound Level (Lt)

The A-weighted sound level below which the sound produces little or no Noise Dose accumula-tion and may be disregarded. It is used for hearing damage risk assessment.


Time Weighted Average Sound Level (TWA, LTWA(TC))

It is the level of a constant sound over the Criterion Duration, that would expose a person to thesame Noise Dose as the actual (unsteady) sound over the same period. If the Exchange Rate is 3dB then the TWA is equal to the Leq.

Where TC=T2-T1 and K is the Exchange Rate Factor. It is used for hearing damage risk assessment.


c 20.05 degC 273+= m sec

c 49.03 degF 460+= ft sec

nL

nsAFL

AFTM

10

5

)(5max

10

log10

LTWA TC Klog101T--- 10

Lp t Ktd

T1

T2

=


Time Weighting

The response speed of the detector in a sound level meter. There are several speeds used.

Slow: The time constant is 1 second (1000 ms). This is the slowest and is commonly used in envi-ronmental noise measurements.

Fast: The time constant is 1/8 second (125 ms). This is a less commonly used weighting but willdetect changes in sound level more rapidly.

Impulse: The time constant is 35ms for the rise and 1.5 seconds (1500 ms) for the decay. The rea-son for the double constant is to allow the very short signal to be captured and displayed.

Vibration

The oscillatory movement of a mechanical system (generally taken to be solid). It is used as abroad descriptor of oscillations.

Wavelength (l)

The distance between peaks of a propagating wave with a well defined frequency. It is related tothe frequency through the following equation

where c is the sound speed and f is the frequency in Hz. It has the dimensions of length.

Wavenumber (k)

A number that is related to the wavelength of sound and is used to compare the size of objects rel-ative to the wavelength or the time delay in sound propagation. It is related to wavelengththrough the following equation

where l is the wavelength, c is the sound speed, f is the frequency in Hz, and w is the radian fre-quency. It has the dimensions of inverse length.

cf--=

k 2

------ 2fc

-------- c----= = =

831C SoundAdvisor© Reference Manual

Larson Davis - a PCB Piezotronics division LarsonDavis.com

P/N I831C Rev M, Firmware version 4.0.5©2019 PCB Piezotronics, Inc.

orldwide Corporate Head uarters3425 Walden AvenueDepew, NY 14043-2495 USA

Toll-free (in the US): 888-258-3222Phone: 716-926-8243USA fax: 716-926-8215

E-mail: [email protected]

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