PREFACEACKNOWLEDQEMENTSSOUND REINFORCEMENT HANDBOOK TABLE OF CONTENTSSOUND REINFORCEMENT HANDBOOK LIST OF ILLUSTRATIONSSection 1. What is a Sound System1. The audio signal1-1 Sound waves1-2 The electrical representation of sound 1-3 Phase1-4 Adding sine waves

2. The basic purpose of sound system3. A conceptual model of a sound system4. Input transducers5. Output transducers6. A practical model of a sound system

Section 2. Frequency Response1. A definition1-1 Basic specification methods1-2 Octave relationships and measurements

2. Frequency response of practical audio devices2-1 Electronic circuits and cables2-2 Microphones2-3 Loudspeakers

3. Voice and instrument ranges3-1 The speaking voice3-2 The singing voice and musical instruments3-3 Harmonics

4. Effect of acoustical factors

Section 3. The Decibel, Sound Level, Related Items1. What is a decibel?1-1 A mathematical definition of the dB1-2 Relative versus absolute levels

2. Relating the decibel to electrical signal levels2-1 dBm2-2 dBu2-3 dBv and dBv2-4 Converting dBv to dBu (or to dBm scross600 ohms)2-5 Relating dBv, dBu and dBm to specifications2-6 dBw

3. Relating the decibel to scoustic levels 3-1 dB SPL3-2 dB PWL

4. What is rms?5. Volume, level and gain6. Loudness6-1 Equal loudness contours and phons6-2 What we can deduce from equal loudness contours6-3 Loudness compensation

Section 4. Dynamic Range1. Dynamic range1-1 A definition1-2 The dynamic range of a typical rock concert1-3 The electrical dynamic range of the sound system1-4 The acoustical dynamic range of the system

2. Headroom2-1 A definition2-2 Why headroom is important

3. Manipulating dynamic range in practical sound system3-1 Why not build a sound system with excess dynamic range?3-2 What happens when the sound system is inadequate?3-3 How to fit wide program dynamics into a sound system with limited dynamic range3-4 How much headroom is adequate?

Section 5. Sound Outdoors1. The inverse square law1-1 Inverse square law calculations

2. Effects of environmental factors2-1 Wind2-2 Temperature gradients2-3 Humidity

3. Feedback control3-1 Maximum gain (available gain before feedback)3-2 Using directional microphones and loudspeakers

Section 6. Sound Indoors1. Boundaries1-1 The absorption coefficient

2. Standing waves2-1 Standing waves in a room

3. Reverberation4. Critical distance4-1 Implications for sound reinforcement

Section 7. Block Diagrams1. General discussion2. Symbolic conventions3. Notational conventions4. Analysis of simple block diagrams5. Summation

Section 8. How to ReadInterpret Specifications1. General disaussion 1-1 Why specs are not always what they seem 1-2 Examples of specs that should be doubted1-3 What to look for

2. Frequency response2-1 Distinguishing frequency response, frequency range, and power bandwidth2-2 Graphic versus printed specs2-3 What is a good frequency response spec?

3. Noise3-1 What is noise?3-2 White noise3-3 Pink noise3-4 Shaping the noise3-5 EIM: a measure of mic preamplifier noise 3-6 Specifying output noise3-7 Other types of noise

4. Harmonic distortion4-1 What is harmonic distortion?4-2 Measuring harmonic distortion?4-3 Factors affecting harmonic distortion specifications

5. Intermodulation distortion5-1 Measuring IM distortion5-2 Sources of IM distortion5-3 How much distortion is tolerable?5-4 Transient intermodulation distortion

6. Input and output impedances6-1 Confusion about input and output impedances6-1-1 Output impedance6-1-2 Input impedance

6-2 The implications of impedance mismatches6-3 Impedance and frequency

7. Standard operating levels7-1 General classification of levels7-2 Expressing the wide power range of a sound system7-3 How impedance relates to level specifications7-3-1 Power vs impedance7-3-2 Overloading an output7-3-3 How the load affects output voltage

7-4 What happens when hi-fi and pro equipment mix7-4-1 Hi-fi output to pro equipment input7-4-2 Pro equipment output to hi-fi input

8. Crosstalk8-1 What causes crosstalk?8-2 Crosstalk in cables8-3 Specification of crosstalk

9. Filter slope rates and turnover frequencies10. Squre wave tests10-1 Oscilloscopes 10-2 What not to expect with square waves

11. Miscellany

Section 9. Why Ears Don't Always Correlate With Specs1. Differerent points of view1-1 Calibrated mics vs ears 1-2 Average ears vs "golden ears"

2. Test equipment measurements listening tests2-1 Test signals versus program material2-2 Location and number of test microphones2-3 Dynamic range

3. Static vs dynamic tests4. Masking effects and equipment imteraction

Section 10. Microphones1. Methods of transduction1-1 Dynamic1-2 Condenser1-3 Electret condenser1-4 Ribbon1-5 Carbon1-6 Piezoelectric

2. Functional design2-1 Hand-held2-2 Stand-mounting2-3 Lavalier2-4 Contact pickup2-5 pressure response2-6 Shotgun2-7 Parabolic2-8 Multi-element arrays2-9 Noise cancelling microphones

3. Acoustical and electrical characteristics3-1 Pickup patterns3-1-1 Omnidirectional3-1-2 Cardioid 3-1-3 Bidirectional or figure-83-1-4 Supercardioid

3-2 Frequency response3-3 Proximity effect3-4 Transient response3-5 Output level or sensitivity3-6 Overload3-7 Impedance3-8 Balanced and unbalanced connections

4. Application information4-1 Windscreens and pop filters4-2 Shock mounts4-3 Phantom power4-4 Effect of the number of open microphones4-5 Gain and microphone placement4-6 Stereo recording

5. Wireless intercom systems5-1 What is a wireless intercom?5-2 Who uses wireless intercoms?5-3 What is the background of wireless intercoms?5-4 Types of wireless intercoms5-5 Frequencies used5-6 Improved range and noise reduction5-7 Evaluating and selecting a system5-8 Conclusions5-9 Glossary of wireless intercom terms

6. Wireless microphone systems6-1 What is a wireless mic?6-2 Who uses wireless mics?6-3 What is the background of wireless mics?6-4 Radio frequencies used6-5 Technical problems6-6 Solutions6-7 Multiple microphone systems6-8 Compatibillty of wireless mic systems6-9 Antenna cables6-10 Evaluating wireless microphone systems6-11 Conclusions6-12 Glossary of wireless microphone terms

Section 11. Preamplifiers, Small Nixers, Mixing Consoles1. General discussion2. Preamplifiers2-1 What are they, and what do they do?2-2 Impedance converters2-3 Phono preamps

3. Mixers4. Consoles4-1 What is a console?4-2 How mixes differ:prepost fader considerations4-3 Panning, summing, and master faders

5. Understanding console specifications5-1 How many input, mixes, and output?5-2 Signal-to-noise ratio5-3 Maximum voltage gain5-4 Headroom5-5 Indicators

6. Transformer isolated versus electronically balanced inputsoutputs6-1 Transformers versus differential amps: price concers6-2 Discrete versus IC differential amps 6-3 The case for the transformer6-4 Transformers and AC safety6-5 More on transformers

7. Gain staging and gain structure7-1 Why does gain have to be manipulated? a review of sound levels fed to the console7-2 Gain control at the microphone input7-3 Input attenuation or padding 7-4 Eliminating other causes of signal-level(gain)related distortion7-4-1 Summing amp overdrive7-4-2 Power amp overdrive

8. Interface with sub-mixers 9. Stage monitor mixing consoles9-1 What is a stage monitor system?9-2 How is a monitor system set up?9-3 Why a monitor console is preferable to a mix from the main house console9-4 The importance of a high quality monitor mix9-5 Other benefits of a separate monitor console 9-6 Polarity (phase) reversal as a tool to fight feedback9-7 Eliminating SCR dimmer noise

10. Microphone splitting10-1 The splitter transformer10-2 Additional isolation for high-noise environments10-3 Splitting a mic without a transformer

11. Reducing feedback in the stage monitor system 11-1 Directinal microphones11-2 Polarity reversal (or "phase" reversal) 11-3 Ringing out a monitor system11-4 Aiming monitor loudspeakers

12. Equipment placement12-1 Additional monitor console placement factors12-2 Main house mixing console placement

Section 12. Power Amplifiers1. General discussion2. Ohm's law related equations2-1 Voltage, resistance and current2-2 Electrical power 2-3 Ohm's law chart2-4 Electrical power and amplifier gain

3. Power ratings of amplifiers3-1 ETC preconditioning3-2 Power bandwidth3-3 Slew rate and output power 3-4 Bridged operation3-5 The effect of clipping

4. The relationship between amplifier power and SPL 5. Matching power amplifiers to loudspeakers5-1 Interpreting loudspeaker power ratings 5-2 Impedance calculations5-3 Constant-voltage distribution systems

Section 13. Loudspeakers1. Introduction2. Common nethods of acoustic transduction2-1 Electromagnetic transduction2-2 Piezoelectric transduction

3. Low frequency drivers3-1 Directinal characteristics of cone drivers

4. Low frequency enclosures 4-1 Vented enclosures4-2 Low frequency horns

5. High frequency drivers6. High frequency horns7. Crossovers7-1 General model7-2 Passive, high level crossovers7-3 Active, low level crossovers7-3-1 Headroom7-3-2 Efficiency 7-3-3 Damping7-3-4 Distortion 7-3-5 Biamp or triamp versus conventional system

8. Full-range loudspeakers8-1 effect of boundary conditions

9. Loudspeaker specifications9-1 Frequeny response9-2 Power handling9-3 Sensitivity9-4 impedance9-5 Directional characteristics

10. Sources of distortion10-1 Over-excursion10-2 Intermodulation distortion10-3 Mechanical defects

11. Typical failure modes11-1 Manufacturing defects11-2 IMproper operation11-3 Failures due to other components in the signal chain

Section 14. Signal Processing Equipment1. Equalizers1-1 General discussion1-2 Common tone controls1-3 Multi-band conventional equalizers1-4 Sweep-type equalizers1-5 Parametric equalizers1-6 Graphic equalizers1-7 Paragraphic equalizers1-8 Tuning a sound system with graphic (or paragraphic) equalization1-9 High pass and low pass filters

2. Reverberation and delay2-1 Reverb chambers2-2 Duct-type reverbsb\2-3 Spring-type reverbs2-4 Plate-type reverbs2-5 Digital reverberation2-6 Tape delay2-7 Digital delay2-8 Analog delay

3. Compressors limiters3-1 General discussion3-2 How compressor/limiters work3-3 Setup adjustments

4. Noise gates expanders4-1 General4-2 Noise gate applications4-3 Expander applications

5. Flangers and phasers5-1 Flanging5-2 Phasing5-3 What to look for

6. Exciters

Section 15. Cabling1. The importance of good cables2. Types of cables, their construction and use 2-1 Electrosttic and electrmagnetic shielding2-2 Cable self-capacitance2-3 Single and dual conductor shielded cables2-4 Strain relief2-5 Unshielded cables and speaker cables2-6 Multicore audio cables ("snakes")

3. Connectors3-1 General3-2 Phone plugs3-3 Phono (pin) connectors3-4 XLR connectors

Section 16. Sound System Test Equipment1. The volt-ohm meter2. The sine wave oscillator3. The oscilloscope4. The phase tester5. The sound pressure level meter6. The real-time analyzer7. The loudness monitor8. Summary

Section 17. The Electronics1. Basic sound system types1-1 Sound reproduction systems1-2 Sound reinforcement systems

2. Developing a logical system architecture2-1 Functional grouping2-2 System examples

3. Basic connections3-1 Signal levels and impedance3-2 Unbalanced and balanced connections

4. Grounding 4-1 Why is proper grounding important?4-2 Ground loops4-3 Basic grounding techniques

5. Using audio signal transformers5-1 Properties and functions of signal transformers5-2 Some practical applications

6. The main power source6-1 Verify the correct mains voltage6-2 Ensure there is a good earth ground 6-3 How to obtain a safety ground when using a two-wire outlet6-4 Improperly wired AC outlets: lifted grounds6-5 Improperly wired AC outlets: lifted neutral6-6 AC safety tips6-7 Turn-on sequencing6-8 Power source integrity

7. Configuring equipment racks8. Troubleshooting8-1 Absence of signal8-2 Undesired signals

Section 18. The loudspeakers1. Analyzing the application1-1 The program material1-2 The environment

2. Directional control2-1 Widenind dispersion2-2 Narrowing dispersion2-3 SPL estimations

3. Placment considerations3-1 Directionality and coverage3-2 Feedback control review3-3 Outdoor sound systems3-4 Controlling feedbackindoors3-5 Loundspeaker placement indoors

4. Connections4-1 Wire size4-2 Connectors4-3 Polarity of connections4-4 General guidelines

5. Setting electronic crossovers5-1 Choice of crossover frequency and slope5-2 Setting up the loudspeaker system5-3 Testing and optimizing the system5-4 High frequency driver protection networks

6. Use of fill systems6-1 Balancing fill systems

7. Testing and Equalization7-1 Single loudspeakers7-2 Multiple loudspeaker systems7-3 Room equalization

Section 19. MIDI1. Interface specifications1-1 Hardware configuration1-2 Data structure1-3 Channel messages1-4 System messages

2. Control of musical instruments2-1 MIDI modes2-2 Controllers2-3 Patch editor/librarian functions2-4 MIDI implementation charts

3. MIDI sequencing3-1 Basic theory3-2 Channels tracks3-3 Hardware vs computer-based esquencers3-4 Typical sequencer features3-4-1 Song editing3-4-2 Step editing3-4-3 Common editing features

4. MIDI data processors4-1 Thru boxes4-2 MIDI mergers4-3 MIDI patchers4-4 Mapping devices4-5 SysEx data storage

5. Automation through MIDI5-1 Instrument patch changes5-2 Signal processors5-3 Console functions5-4 Sync to media

6. Troubleshooting6-1 Lack of response6-2 Stuck notes6-3 MIDI feedback6-4 MIDI time delays

Section 20. Synchronization1. General discussion1-1 Basic theory1-2 Pulse methods1-3 Timepiece methods

2. AMPTW/EBU time code2-1 Signal structure2-2 Frame rates and line references2-3 Longitudinal, vertical interval and visible time code2-4 Machine control2-4-1 Slave code error2-4-2 Slave code offset2-4-3 Flying offsets2-4-4 Slew2-4-5 Advanced transport controls2-4-6 Event triggers

2-5 Time code and audio tape 2-5-1 Printing SMPTE time code2-5-2 Copying SMPTE time code

2-6 SMPTE-to-MIDI conversion

3. Edit decision

Appendix A. LogarithmsA.1 Raising Numbers to a Power: The Key to LogsA.2 Simple Logs (and Antilogs) to the Base 10A.3 Less Obvious Logs to The Base 10A.4 Mathematical Properties of Logs A.5 One More Look At Logs and Decibels

IndexColophon