Digital Audio

Digital AudioDigital AudioDigital AudioDigital AudioThe mini series...The mini series...

Digital Audio DefinitionDigital Audio Definition

A sequence of discrete samples taken from a continuous sound (audio) waveform. Tens of thousands of samples are taken each second. Each sample represents the intensity of the sound pressure wave at that instant. Apart from the sampling frequency, the other parameter is the digital encoding of each sample including the number of bits used. The encoding may be linear, logarithmic or mu-law.

Digital audio is typically created by taking 16-bit samples over a spectrum of 44.1 thousand cycles per second (kHz), this means that CD quality sound requires 1.4 million bits of data per second. Digital telephone systems use lower sample rates.

A sequence of discrete samples taken from a continuous sound (audio) waveform. Tens of thousands of samples are taken each second. Each sample represents the intensity of the sound pressure wave at that instant. Apart from the sampling frequency, the other parameter is the digital encoding of each sample including the number of bits used. The encoding may be linear, logarithmic or mu-law.

Digital audio is typically created by taking 16-bit samples over a spectrum of 44.1 thousand cycles per second (kHz), this means that CD quality sound requires 1.4 million bits of data per second. Digital telephone systems use lower sample rates.

http://dictionary.reference.com/browse/audio

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http://dictionary.reference.com/browse/mu-law

http://dictionary.reference.com/browse/audio

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http://dictionary.reference.com/browse/mu-law

History of digital audioHistory of digital audio

1877 the phonograph is born (by Thomas Alva Edison)

1878 first music put on record: Yankee Doodle

1888 Edison introduces the motor-driven phonograph

1901 Experimental optical recordings are made on motion picture film.

1910 Enrico Caruso is heard in the first live broadcast from the Metropolitan Opera, NYC

1877 the phonograph is born (by Thomas Alva Edison)

1878 first music put on record: Yankee Doodle

1888 Edison introduces the motor-driven phonograph

1901 Experimental optical recordings are made on motion picture film.

1910 Enrico Caruso is heard in the first live broadcast from the Metropolitan Opera, NYC


1913 The first “talking movie” is demonstrated by Edison using his Kinetophone process, a cylinder player mechanically synchronized to a film projector.

1919 the Radio Corporation of America (RCA) is founded.

1925 The first electrically recorded 78 rpm disks appear. RCA works on the development of the ribbon microphone.

1928 Dr. Georg Neumann founds a company in Germany to manufacture his condenser microphone.

1913 The first “talking movie” is demonstrated by Edison using his Kinetophone process, a cylinder player mechanically synchronized to a film projector.

1919 the Radio Corporation of America (RCA) is founded.

1925 The first electrically recorded 78 rpm disks appear. RCA works on the development of the ribbon microphone.

1928 Dr. Georg Neumann founds a company in Germany to manufacture his condenser microphone.


1932 The first cardioid ribbon microphone is patented by Dr. Harry F. Olson of RCE, using a field coil instead of a permanent magnet.

1936 Von Braunmuhl and Weber apply for a patent on the cardioid condenser microphone.

1940 Walt Disney’s “Fantasia” is released with eight-track stereophonic sound.

1947 Ampex produces its first tape recorder, the Model 200

1932 The first cardioid ribbon microphone is patented by Dr. Harry F. Olson of RCE, using a field coil instead of a permanent magnet.

1936 Von Braunmuhl and Weber apply for a patent on the cardioid condenser microphone.

1940 Walt Disney’s “Fantasia” is released with eight-track stereophonic sound.

1947 Ampex produces its first tape recorder, the Model 200


1948 The Audio Engineering Society (AES) is formed in New York City.

1949 RCA introduces the microgroove 45 rpm, large-hole, 7in record and record changer adaptor.

1954 The first commercial 2-track stereo tapes are released.

1956 Les Paul makes the first 8-track recordings

1963 The Beach Boys contract Sunn Electronics to build the first large full-range sound system for their rock music concert tour.

1948 The Audio Engineering Society (AES) is formed in New York City.

1949 RCA introduces the microgroove 45 rpm, large-hole, 7in record and record changer adaptor.

1954 The first commercial 2-track stereo tapes are released.

1956 Les Paul makes the first 8-track recordings

1963 The Beach Boys contract Sunn Electronics to build the first large full-range sound system for their rock music concert tour.


1969 Bill Hanley and Company designs and builds the sound system for the Woodstock Music Festival.

1975 Digital Tape recording begins to take hold in professional audio studios.

1980 Sony introduces a palm-sized stereo cassette tape player called a walkman.

1981 Philips demonstrates the Compact Disc (CD)

1982 Sony released the first CD player

1969 Bill Hanley and Company designs and builds the sound system for the Woodstock Music Festival.

1975 Digital Tape recording begins to take hold in professional audio studios.

1980 Sony introduces a palm-sized stereo cassette tape player called a walkman.

1981 Philips demonstrates the Compact Disc (CD)

1982 Sony released the first CD player


1984 The Apple Corporation markets the macintosh computer.

1991 Apple debuts the “QuickTime” multimedia format.

1992 The Philips DCC and Sony’s MiniDisc, using digital audio data-reduction, are offered to consumers as record/play hardware and software.

1996 Record labels begin to add multimedia files to new releases, calling them “enhanced CDs.”

1998 MP-3 Players for downloaded Internet audio appear.

1984 The Apple Corporation markets the macintosh computer.

1991 Apple debuts the “QuickTime” multimedia format.

1992 The Philips DCC and Sony’s MiniDisc, using digital audio data-reduction, are offered to consumers as record/play hardware and software.

1996 Record labels begin to add multimedia files to new releases, calling them “enhanced CDs.”

1998 MP-3 Players for downloaded Internet audio appear.


PhonographPhonograph RecordRecord Elec. PhonographElec. Phonograph 78 RPM 78 RPM

Ribbon Microphone

Ribbon Microphone

Condenser MicrophoneCondenser Microphone

Cardioid Ribbon Microphone

Cardioid Ribbon Microphone

Cardioid Condenser Microphone

Cardioid Condenser Microphone


Tape recorderTape recorder 2 track stereo2 track stereo8 track stereo8 track stereoWoodstock Woodstock

Cassette Tape

Cassette Tape

WalkmanWalkman CompactDisc

CompactDisc

First CDPlayer

First CDPlayer


1st MacintoshComputer

1st MacintoshComputer MiniDiscMiniDisc 1st MP3 Player1st MP3 Player

Determining Audio File SizeDetermining Audio File Size

Sample Rate:

The number of times per second a recording device samples sound waves, expressed in kilohertz (kHz).

a sample is a small fragment of sound waves.

it takes many samples to accurately reproduce sound.

the higher the sampling rate the higher the quality of audio.commercial CDs are recorded at 44.1 kilohertz (kHz) 44,100 samples per sec.

Sample Rate:

The number of times per second a recording device samples sound waves, expressed in kilohertz (kHz).

a sample is a small fragment of sound waves.

it takes many samples to accurately reproduce sound.

the higher the sampling rate the higher the quality of audio.commercial CDs are recorded at 44.1 kilohertz (kHz) 44,100 samples per sec.


Sample Size:

The number of bits of data in an audio sample: also called audio resolution.

The more bits the better the sound quality of the recording.

example: 16 bit sound file is a higher quality audio file then an 8 bit file.

Sample Size:

The number of bits of data in an audio sample: also called audio resolution.

The more bits the better the sound quality of the recording.

example: 16 bit sound file is a higher quality audio file then an 8 bit file.


Number of Channels:

Monaural or Mono is a single channel audio.

Stereophonic or stereo has two channels of audio.

Surround sound has multiple channels (currently 5-7)

The more channels of audio the more realistic the sound and the larger the audio file.

Number of Channels:

Monaural or Mono is a single channel audio.

Stereophonic or stereo has two channels of audio.

Surround sound has multiple channels (currently 5-7)

The more channels of audio the more realistic the sound and the larger the audio file.


Time span of recording:

The Length of the Recording

The longer the length of the recording, the larger the file size.

Time span of recording:

The Length of the Recording

The longer the length of the recording, the larger the file size.

StreamingAudioStreamingAudio

Streaming:

Streaming refers to the process of transmitting audio/video files, over the Internet, that can begin playing as the remaining data is temporarily transferring to your computer.

first developed by Real Audio.

user friendly because the audio can be listened to as the file is loading.

user does not have to wait for the completed file to load to begin hearing the audio.

Streaming:

Streaming refers to the process of transmitting audio/video files, over the Internet, that can begin playing as the remaining data is temporarily transferring to your computer.

first developed by Real Audio.

user friendly because the audio can be listened to as the file is loading.

user does not have to wait for the completed file to load to begin hearing the audio.


Compression:

a process used to reduce the size of a file.

the process can be lossless(no data permanently discarded during the compression) or Lossy(some audio data is discarded during the compression).

the lossless process provides full audio sound but can create a large file, causing problems with streaming. With lossy compression more data is lost as the compression increases

Compression:

a process used to reduce the size of a file.

the process can be lossless(no data permanently discarded during the compression) or Lossy(some audio data is discarded during the compression).

the lossless process provides full audio sound but can create a large file, causing problems with streaming. With lossy compression more data is lost as the compression increases


Codec: stand for COmpression/DEcompress, software is used to compress the file before transmitting and to decompress it at the receiving end.

Transcoding: converts incompatible or obsolete data into a more suitable format.

Bandwidth: the rate of data transferred, in a given amount of time, over a network.

Codec: stand for COmpression/DEcompress, software is used to compress the file before transmitting and to decompress it at the receiving end.

Transcoding: converts incompatible or obsolete data into a more suitable format.

Bandwidth: the rate of data transferred, in a given amount of time, over a network.

Audio ScriptsAudio Scripts

PSA (Public Service Announcement)Announcements that inform the public about safety and health information, community services or public affairs. Much like a commercial but not for profit

Commercial: a paid advertisement or promotional announcement.

Plays: drama, comedy or mystery with a storyline/plot

Songs: a short metrical composition intended or adapted for singing

PSA (Public Service Announcement)Announcements that inform the public about safety and health information, community services or public affairs. Much like a commercial but not for profit

Commercial: a paid advertisement or promotional announcement.

Plays: drama, comedy or mystery with a storyline/plot

Songs: a short metrical composition intended or adapted for singing

Digital Audio

EquipmentDigital Audio

Equipment

Computer and or mobile device: What will you be using? Mac, PC, Ipod, etc. (demonstrate Belkin tune talk on ipod).

Mixer/Audio Board: Look at handout 5.01.01. What items on an audio board will you need for your recording?

What microphone will you need? (mic info on next slide).

Computer and or mobile device: What will you be using? Mac, PC, Ipod, etc. (demonstrate Belkin tune talk on ipod).

Mixer/Audio Board: Look at handout 5.01.01. What items on an audio board will you need for your recording?

What microphone will you need? (mic info on next slide).

MicrophonesMicrophones

Condenser: microphone consisting of a capacitor with one plate fixed and the other forming the diaphragm moved by sound waves

Dynamic: A microphone whose sound pickup device consists of a diaphragm that is attached to a movable coil

Piezoelectric:contain ceramic or quartz crystals linked with a diaphragm or directly exposed to acoustic waves. This arrangement reduces the electrical noise and output impedance

Wireless: is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated.

Condenser: microphone consisting of a capacitor with one plate fixed and the other forming the diaphragm moved by sound waves

Dynamic: A microphone whose sound pickup device consists of a diaphragm that is attached to a movable coil

Piezoelectric:contain ceramic or quartz crystals linked with a diaphragm or directly exposed to acoustic waves. This arrangement reduces the electrical noise and output impedance

Wireless: is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated.

http://en.wikipedia.org/wiki/Microphone

http://en.wikipedia.org/wiki/Microphone

Digital Audio


Equipment

Speakers: electroacoustic device, often housed in a cabinet, that is connected as a component in an audio system, its function being to make speech or music audible. (surround sound, mono, etc.)

Headsets: a device consisting of one or two earphones with a headband for holding them over the ears and sometimes with a mouthpiece attached. (which kind will help you accomplish your objective?)

Speakers: electroacoustic device, often housed in a cabinet, that is connected as a component in an audio system, its function being to make speech or music audible. (surround sound, mono, etc.)

Headsets: a device consisting of one or two earphones with a headband for holding them over the ears and sometimes with a mouthpiece attached. (which kind will help you accomplish your objective?)

Digital Audio


Equipment

• CABLES AND CONNECTORS• CABLES AND CONNECTORS

Mini Plug - 1/8 in. TRS Plug

The worst audio quality. The choice of modern audio players and consumer electronics. This type of audio connection typically offers a decent signal for no-professional applications. TRS in the name stands for Tip, Ring, Sleeve. The number of rings tell the user if the plug is stereo (two rings) or mono (one ring).

Phono Plug - 1/4 in. TRS Plug

A better alternative to the mini plug. This type of connection is used by professionals yet isn’t the preferred connection. Widely used in the music industry to connect some microphone applications, connect speakers, amplifiers, and guitars this plug has an inherent flaw. It can easily be unplugged. The number of rings also tell how many channels the cable is capable of handling.

Canon XLR - Female End

The best audio quality. The choice of profession applications. This type of audio connection typically offers an analog signal.

Canon XLR - Male end

The best audio quality. The choice of profession applications. This type of audio connection typically offers an analog signal.The button at the top of the connector prevents the cable from accidentally being unplugged. The cable cannot be removed without pushing this button.

Digital Audio


Equipment


Canon XLR port

This port is used to connect XLR cables to a device. In this application a Microphone is plugged into this location.

MIDI Port

This is a MIDI port. The MIDI plug allows for input of musical notes from electronic instruments into a computer.

RCA Phono port

This is a RCA Phono Port. Notice that the port is color coded. The red typically is right and the white is left channel audio. In this application a red and white RCA cable was used to connect a digital signal input and output.

Phono Plug - 1/4 in. TRS Plug

This port connects phono plugs to a device. In this application the left and right audio monitor channels are output.

Digital Audio


Equipment


RCA Plug

This common audio and video connector has been around since the 1940’s and is still used in modern electronics. It was originally used to connect record players to amplifiers. Today it is used in many different applications but isn’t the preferred connection for high quality video and audio. The longer the cable the greater the chance of interference.

6 & 4 pin Firewire cable plug

The most common way to connect digital audio and video to a computer. It has been adapted to audio applications. The cable has very fast data transfer rates and is often used to connect portable hard drives. The term Firewire is a brand name from Apple Inc. and is known internationally as IEEE 1394 High Speed Serial Bus. The four pin connector is the smaller inset image.

A & B Type USB Plug

This type of connection was designed to allow universal connection between multiple devices.USB stands for Universal Serial Bus. The connection is used for cameras, audio devices, and data. It is the most commonly used computer connection in modern computers. The inset image is also a USB plug it is a B Type plug.

B Type USB Port

This plug is used in an audio application. It connects an audio board to a computer. It is also used to connect a computer to many many things.

MicrophonePIckup PatternsMicrophonePIckup Patterns

Omnidirectional:Sound that comes from

all directions

Omnidirectional:Sound that comes from

all directions

Unidirectional:

A pick-up pattern which is more sensitive to sound arriving from one

direction than from any other.

Unidirectional:

A pick-up pattern which is more sensitive to sound arriving from one

direction than from any other.

Cardioid Cardioid Hypercardioid Hypercardioid


Bidirectional:

will capture sound from the front and back of the

diaphragm.

Bidirectional:

will capture sound from the front and back of the

diaphragm.


Shotgun:

type of pickup pattern that is highly directional.

captures sound in the direction the microphone is pointed.

subject does not have to be in close proximity to the mic.

Shotgun:

type of pickup pattern that is highly directional.

captures sound in the direction the microphone is pointed.

subject does not have to be in close proximity to the mic.

Audio File FormatsAudio File Formats

MP3: standard format for music file sent over the Internet.

WAV: standard for sound files on Microsoft & IBM PCs. Does not compress for audio as much as mp3 and other formats.

MIDI (Musical Instrument Digital Interface): format for recording music from electronic instruments.

MP3: standard format for music file sent over the Internet.

WAV: standard for sound files on Microsoft & IBM PCs. Does not compress for audio as much as mp3 and other formats.

MIDI (Musical Instrument Digital Interface): format for recording music from electronic instruments.

Audio File FormatsAudio File Formats

AIFF (audio interchange file format): a common format for storing and transmitting sampled sound. The format was developed by Apple Computer and is the standard audio format for Macintosh computers

AAC (Advanced Audio Coding): standard audio file format for portable devices such as phones and gaming systems.

WMA (Windows Media Audio):Windows streaming audio file format. WMA files, which use the “.wma” file extension, can be of any size compressed to match many different connection speeds, or bandwidths.

AIFF (audio interchange file format): a common format for storing and transmitting sampled sound. The format was developed by Apple Computer and is the standard audio format for Macintosh computers

AAC (Advanced Audio Coding): standard audio file format for portable devices such as phones and gaming systems.

WMA (Windows Media Audio):Windows streaming audio file format. WMA files, which use the “.wma” file extension, can be of any size compressed to match many different connection speeds, or bandwidths.

Digital Audio

Documents

Transcript of Digital Audio