Audio Recording Terms Glossary/Index

Interactive Version For Pro Audio Specialist Study Module

Designed for Recording Institute Of Detroit Pro Audio Specialist students' use in classroom or Study & Development Center or for home study.


Select the first letter of the word from the list above to jump to appropriate section of the glossary.

- A -

Absorption - Short for the term Acoustical Absorption (quality of a surface or substance to take in, not reflect, a sound wave).

AC - An abbreviation of the term Alternating Current (electric current which flows back and forth in a circuit; all studio signals running through audio lines are AC).

Acoustic / Acoustical - Having to do with sound that can be heard by the ears.

Acoustic Amplifier - The portion of the instrument which makes the vibrating source move more air or move air more efficiently; this makes the sound of the instrument louder. Examples of acoustic amplifiers include: 1) The body of an acoustic guitar, 2) The sounding board of a piano, 3) The bell of a horn and 4) The shell of a drum.

Acoustic Echo Chamber - A room designed with very hard, non-parallel surfaces and equipped with a speaker and microphone; dry signals from the console are fed to the speaker and the microphone will have a reverberation of these signals that can be mixed in with the dry signals at the console.

Acoustical Absorption - The quality of a surface or substance to take in the sound wave and not reflect it or pass it through, or an instance of this.

A/D - An abbreviation of Analog to Digital Conversion (the conversion of a quantity that has continuous changes into numbers that approximate those changes), or Analog to Digital Converter.

ADAT - A trademark of Alesis Corporation designating its modular digital multitrack recording system released in early 1993.

ADSR - The letters A, D, S &R are the first letters of: Attack, Decay, Sustain and Release. These are the various elements of volume changes in the sounding of a keyboard instrument.

AES - An abbreviation of Audio Engineering Society.

AES/EBU Professional Interface - A standard for sending and receiving digital audio adopted by the Audio Engineering Society and the European Broadcast Union.

Aliasing - A sampler mis-recognizing a signal sent to it that is at a frequency higher than the Nyquist Frequency.  Upon playback, the system will provide a signal at an incorrect frequency (called an alias frequency). Aliasing is a kind of distortion.

Alternating Current - Electric current which flows back and forth in a circuit.

Ambience - The portion of the sound that comes from the surrounding environment rather than directly from the sound source.

Ambient Field - A term with the same meaning as the term Reverberant Field (the area away from the sound source where the reverberation is louder than the direct sound).

Ambient Micing - Placing a microphone in the reverberant field (where the reverberation is louder than the direct sound) so as to do a separate recording of the ambience or to allow the recording engineer to change the mix of direct to reverberant sound in recording.

Amp - 1) An abbreviation of the term Amplifier (A device which increases the level of an electrical signal. 2) An abbreviation of Ampere (the unit of current). 3) An abbreviation of amplitude (the height of a waveform above or below the zero line).

Text Reference (1): Lesson 10

Ampere - The unit of current, abbreviated Amp.

Amplification - An increasing of signal strength.

Amplifier - A device which increases the amplitude (level) of an electrical signal (making it louder).

Text Reference: Lesson 10 - Illustration

Amplitude - The height of a waveform above or below the zero line.

Analog (Analogue) - Representative, continuous changes that relate to another quantity that has a continuous change.

Analog Recording - A recording of the continuous changes of an audio waveform.

Text Reference: Lesson 40

Analog To Digital Converter - The device which does the conversion of a quantity that has continuous changes (usually of voltage) into numbers that approximate those changes.

Assign - To choose to which place an output is going to be sent.

Assistant Engineer - A less elevated version of the term Second Engineer. Experienced seconds often place microphones, operate tape machines, break down equipment at the session end and keep the paperwork for the session.

Atom - The smallest particle which makes up a specific substance. It's composed of a center around which electrons revolve.

Text Reference: Lesson 2 - Illustration

Attack - The rate the sound begins and increases in volume.

Attenuation - A making smaller: reduction of electrical or acoustic signal strength.

Audio - Most often referring to electrical signals resulting from the sound pressure wave being converted into electrical energy.

Text Reference: Lesson 2

Automatic Gain Control (Automatic Volume Control) - A compressor with a very long release time used to keep the volume of the audio very constant.

Automation - In consoles, a feature that lets the engineer program control changes (such as fader level) so that upon playback of the multitrack recording these changes happen automatically.

Aux Send - Short for the term Auxiliary Send (a control to adjust the level of the signal sent from the console input channel to the auxiliary equipment through the aux buss.

Text Reference: Lesson 25

Auxiliary Equipment - Effects devices separate from but working with the recording console.

Axis - A line around which a device operates. Example: In a microphone, this would be an imaginary line coming out from the front of the microphone in the direction of motion of the diaphragm.

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- B -

Baffles - Sound absorbing panels used to prevent sound waves from entering or leaving a certain space

Balance - 1) The relative level of two or more instruments in a mix, or the relative level of audio signals in the channels of a stereo recording. 2) To make the relative levels of audio signals in the channels of a stereo recording even.

Balance Control - A control on a stereo amplifier that when moved clockwise will make the right channel louder (and the left channel softer) and will do the reverse when moved counter-clockwise. 

Balanced - 1) Having a pleasing amount of low frequencies compared to mid-range frequencies and high frequencies. 2) Having a pleasing mixture of the various instrument levels in an audio recording. 3) Having a fairly equal level in each of the stereo channels. 4) A method of interconnecting electronic gear using three-conductor cables. 

Text References: Lesson33

Band - 1) A range of frequencies, sometimes identified by the center frequency of the range.  2) One of the selections on a compact disk or DVD.  3) A group of musicians playing together.

Band Track - 1) A mixdown of a song without the lead vocal or without the lead and background vocals. 2) A term with the same meaning as the term Rhythm Track. 3) The recording of the rhythm instruments in a music production. 

Bandwidth - 1) The range of frequencies over which a tape recorder, amplifier or other audio device is useful. 2) The number of frequency octaves affected by an equalization setting.

Text Reference: Lesson 21

Bank - 1) A collection of sound patches (data as to the sequence and operating parameters of the synthesizer generators and modifiers) in memory. 2) A group of sound modules as a unit. 

Bar - A term meaning the same thing as the term Measure (the grouping of a number of beats in music, most-often four beats). 

Barrier Micing - A method of placing the head of a microphone as close as possible to a reflective surface, preventing phase cancellation

Basic Session - The First session in recording an audio production to record the Basic Tracks

Bass - 1) The lower range of audio frequencies up to approximately 250 Hz. 2) Short for Bass Guitar

Text References: Lesson 6 Illustration

Bass Roll Off - An electrical network built into some microphones to reduce the amount of output at bass frequencies when close-micing.

Text References:  Lesson 7 Illustration

Beat - 1) The steady even pulse in music.2) The action of two sounds or audio signals mixing together and causing regular rises &.falls in volume.

Beats Per Minute - The number of steady even pulses in music occurring in one minute and there fore defining the tempo of the song. 

Bi - A prefix meaning two.

Bi-Directional Pattern - A microphone pick up pattern which has maximum pick up directly in front and directly in back of the diaphragm and least pick up at the sides. 

Text Reference: Lesson 5 - Illustration

Biamplification - The process of having of having low-frequency speakers and high-frequency speakers driven by separate amplifiers.

Text Reference: Lesson 36

Binary - A numbering system based on two. In binary there are two symbols used ("l" and "0").  

Bit - The smallest unit of digital information representing a single "0" or 1. 

Blending - 1) A condition where two signals mix together to form one sound or to give the sound of one sound source or one performance. 2) Mixing the left and right signal together slightly which makes the instruments sound closer to the center of the performance stage. 3) A method of panning during mixing where instruments are not panned extremely left or right.  

Board - 1) Another, less formal, term for Console. 2) A set of controls and their housing which control all signals necessary for recording and for mixing. 3) A slang shortening of the term Keyboard Instrument.

Boom - 1) A hand-held, telescoping pole used to hold the microphone in recording dialogue in film production. 2) A telescoping support arm that is attached to a microphone stand and which holds the microphone. 3) Loosely, a boomstand

Boomstand - A microphone stand equipped with a telescoping support arm to hold the microphone.  

Boost - To increase gain, especially to increase gain at specific frequencies with an equalizer.

Bouncing - Alternate name for Ping-Ponging (playing several tacks with sync playback through a console to mix them together and record them on an open track). 

BPM - An abbreviation of Beat Per Minute (the number of steady even pulses in music occurring in one minute and therefore defining the tempo).  

Bulk Dump - Short for System Exclusive Bulk Dump (a method of transmitting data, such as the internal parameters of a MIDI device to another MIDI device). 

Buss (Bus) - A wire carrying signals to some place, usually fed from several sources. 

Text Reference:  Lesson 13

Byte - A grouping of eight information bits.

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- C -

Cancellation - A shortening of the term Phase Cancellation (the energy of one waveform significantly decreasing the energy of another waveform because of phase relationships at or close to 180 degrees).

Capacitor - An electronic device that is composed of two plates separated by an insulator.

Text Reference: Lesson 3

Capacitance - The property of being able to oppose a change in voltage or store an electrical charge.

Capsule - 1) The variable capacitor section of a condenser microphone. 2) In other types of microphones, the part of the microphone that includes the diaphragm and the active element.

Cardioid Pattern - A microphone pick up pattern, which has maximum pick up from the front, less pick up from the sides, and least pick up from the back of the diaphragm.

Text Reference: Lesson 5 - Illustration

Cascade - To set and interconnect two mixers so that the stereo mixing buss(es) of the first mixer feeds the stereo buss(es) of a second mixer.

CD - An abbreviation of the term Compact Disc (a small optical disk with digital audio recorded on it).

CD-ROM - An abbreviation of the term Compact Disc, Read Only Memory (A Compact Disc used to store digital data, such as large programs, that can be read by a computer).

Center Frequency - The frequency of the audio signal that is boosted or attenuated most by an equalizer with a peak equalization curve.

Text Reference: Lesson 21

Central Processing Unit - 1) The main "brain" chip of a computer that performs the calculations and execution of instructions. 2) The main housing of a computer that contains the "brain" chip as opposed to other pieces of the computer system such as keyboards, monitors, etc.

Chamber - 1) An Echo Chamber (a room designed with very hard, non-parallel surfaces equipped with a speaker and microphone so that when dry signals from the console are fed to the speaker, the microphone will have a reverberation of these signals that can be mixed in with the dry signals at the console). 2) A program in a delay/reverb effects device that simulates the sound of an Echo Chamber.

Chase - The automatic adjusting of the speed of a recorder (or sequencer) to be time with another recorder.

Channel - 1) In multitrack tape machines, this term means the same thing as the term Track (one audio recording made on a portion of the width of a multitrack tape). 2) A single path that an audio signal travels or can travel through a device from an input to an output.

Charge - The electrical energy of electrons.   The energy is in the form of a force that is considered negative and repels other like forces (other electrons) and attracts oppposite (positive) forces.

Chip - 1) A slang term with the same meaning as the term IC (a miniature circuit of many components that is in small, sealed housing with prongs to connect it into equipment). 2) The thread cut away from the master lacquer to make the groove, while disc recording.

Chord - Three or more musical pitches sung or played together.

Chorus - 1) The part of The song that is repeated and has the same music and lyrics each time; the chorus will usually give the point of the song. 2) A musical singing group that has many singers. 3) A delay effect that simulates a vocal chorus by adding several delays with a mild amount of feedback and a medium amount of depth. 4) A similar effect created in some synthesizers by detuning (reducing the pitch of, slightly) and mixing it with the signal that has regular tuning and with a slight delay.

Text Reference(3):  Lesson 30

Chorusing - 1) A term meaning the same thing as Chorus (Definition 3 or 4). 2) In some delay effects devices, a term used to mean the term Depth (the amount of change in the controlled signal by the control signal).

Text Reference(2):  Lesson 30

Circuit - 1) One complete path of electric current. 2) Similar to definition 1, but including all paths and components to accomplish one function in a device.

Text Reference: Lesson 2 - Illustration Page

Clicking - Pressing and immediately releasing the switch on a computer's mouse.

Clip - The action of deforming a waveform during overload.

Text Reference:  Lesson 11   -  Ilustration

Clock Signal - The signal put out by a circuit that generates steady even pulses or steady codes used for synchronization.

Close Micing - A technique of placing a microphone close to the sound source (within one foot) in order to pick up mainly the direct sound and to avoid picking up leakage or ambience.

Coax - Two-conductor cable consisting of one conductor surrounded by a shield.

Coincident Microphones (Coincident Pair) - Two microphones whose heads are placed as lose as possible to each other so that the path length from any sound source to either microphone is for all practical purposes, the same.

Comb Filter - 1) The frequency response achieved by mixing a direct signal with a delayed signal of equal strength especially at short delays. Diagram  2) Loosely used to also describe effects that can be achieved with comb filtering as part of the processing.

Compact Disc - A small optical disk with digital audio recorded on it.

Compact Disc, Interactive - A Compact Disc, usually containing audio, video, and text, which the user can interact with in that the display or playback changes after the user performs some action.

Compact Disc, Read Only Memory - A Compact Disc used to store digital data, such as large programs, that can be read by a computer.

Compact Disc Recordable- A blank Compact Disc that can be recorded on one time.

Compander - 1) A two section device that is used in noise reduction systems. The first section compresses the audio signal, before it is recorded, and the second section, expands the signal after recording. 2) In Yamaha brand digital consoles, a signal processing function that applies both compression and expansion to the same signal.

Compression Ratio - How many dB the input signal has to rise above the threshold for every one dB more output of a compressor or limiter.

Text Reference:  Lesson 18

Compression Driver - The unit that feeds a sound pressure wave into the throat of a horn (in a horn loudspeaker).

Text Reference: Lesson 37

Compressor - A signal processing device that does not allow as much fluctuation in the level of the signal above a certain adjustable or fixed level.

Text Reference:  Lesson 16

Condenser - An older term meaning the same thing as Capacitor (an electronic device which is composed of two plates separated by an insulator and can store charge) but sill in common use when referring to a microphone's active element.

Text Reference: Lesson 3

Condenser Microphone - A microphone which converts sound pressure changes into changes of capacitance.   The capacitance changes are then converted into electrical voltage variations (an audio signal).

Text Reference: Lesson 3 - Illustration

Console - A set of controls and their housing, which control all signals necessary for recording and mixing.

Consumer Format (Consumer DIF) - A standard adopted by IEC for sending and receiving digital audio based on The AES Professional Interface.

Contact Microphone - A device that senses vibrations and puts out an audio signal proportional to the vibrations.

Controller - 1) In MIDI, a device that generates a MIDI signal to control synthesizers, sound modules or sample playback units. 2) A remote control unit for a multitrack tape machine which controls transport functions as well as monitor selection switching functions and record ready/safe status of each track. 3) Any device generating a control voltage or signal fed to another device's control input.

Corner Frequency - Same as Cut-Off Frequency (the highest or lowest frequency in the pass band of a filter). (NOUN]

CPU - Abbreviation of Central Processing Unit (The main "brain" chip of a computer or the main housing of a computer that contains the "brain" chip).

Critical Distance - The point a distance away from the sound source where the direct sound and the reverberant sound are equal in volume.

Crossover (Crossover Network) - A set of filters that "split" the audio signal into two or more bands (two or more signals, each of which have only some of the frequencies present).

Text Reference: Lesson 35

Crossover Frequency - 1) The frequency that is the outer limit of one of the bands of a crossover. 2) In the Lexicon 480L delay/reverberation effects unit, the frequency at which the bass frequency reverb time is in effect rather than the mid frequency reverb time.

Text Reference: Lesson 35

Crosstalk - Leakage of an audio signal into a channel that iris not intended to be in, from an adjacent or nearby channel.

Cue - 1) The signal fed back to the musicians through headphones. 2) To set the tape or disc so that the intended selection will immediately play when the tape machine or player is started.3) A location point entered into a computer controlling the playback or recording of a track or tape. 4) In MCI brand tape machines, a term meaning the same thing as Sync Playback (where the record head is used as a playback head for those tracks already recorded).

Cue Send Control - A control that will adjust the amount of signal sent to a cue buss from a console channel.

Current - The amount of electron charge passing a point in a conductor per unit of time.

Cut - 1) One selection (one song) on a pre4ecorded music format. 2) A term with the same meaning as Mute (to turn off a channel or a signal). 3) To reduce gain of a particular band of frequencies (with an equalizer). 4) To not pass a particular band of frequencies (said of a filter)

Text References: (3): Lesson 21   (4):  Lesson 35

Cut-Off Frequency (Turnover Frequency) - 1) The highest or lowest frequency in the pass band of a filter. 2) The highest or lowest frequency passed by an audio device (the cut-off frequency is usually considered to be the first frequency to be 3 dB lower than a reference frequency in the middle of the bandwidth of the device)

Text Reference:   Lesson 35

Cut-off Rate (Slope)- The number of dB that a filter reduces the signal for each octave its frequency past the filter's cut-off frequency (outside of the pass band).

Text Reference:   Lesson 35

Cycle - 1) An alternation of a waveform which begins at a point, passes through the zero line, and ends at a point with the same value and moving in the same direction as the starting point. 2) On a Solid State Logic Console, a command to have the console computer control the tape machine to play and replay a certain section of the tape.

Text Reference:  Lesson 6

Cycles Per Second - A unit used in the measure of frequency, equivalent to Hertz. Cycles Per Second is an outdated term replaced by Hertz in 1948.

Text Reference:  Lesson 6

Cyclic Redundancy Checking Code - An digital error detection code used in digital recording.

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- D -

D/A - Abbreviation of the term Digital To Analog Converter, a device that changes digital data numbers (digital audio signal) into discrete voltage level.

Daisy Chain - 1) A hook up of several devices where the audio signal has to pass through one device to reach the second device and through the second device to reach the third device. 2) In MIDI, a hook up of MIDI devices where the MIDI signal has to pass though each device to reach the next device.

DAT - An abbreviation of Digital Audio Tape and a standard format for recording digital audio on specially designed small cassette tapes.

Data - 1) Information, usually letters, words and commands. 2) An analog signal in early console automation systems made from the control voltages feeding VCA's (voltage controlled amplifiers).

DAW - An abbreviation of Digital Audio Workstation (a dedicated device that is both a recorder and mixer for Digital Audio).

dB - An abbreviation of the term Decibel, a unit used in comparing signal strengths.

Text Reference:  Lesson 17

dBm - 1) Decibels of audio power present compared to one milliwatt of power in a 600 ohm load. 2) Very incorrectly and too commonly used to designate the reference voltage of .775 volts of audio signal strength regardless of impedance.

dBSPL - The sound pressure level present compared in dB to the standard sound pressure reference level representing "no" sound (a sound pressure level that about 50% of the people would say there was no sound present).

dBu (dBv) - The audio voltage present compared in dB to the level of .775 volts of audio voltage in any impedance.

dBx - A Manufacturer (brand) of noise reduction systems, dynamic processing equipment and other audio gear.

DC - Abbreviation of the term Direct Current (electric current flowing in one direction only).

Dead - 1) Referring to an acoustically absorbent area or space. 2) A slang term for broken.

Decay - 1) The rate of reduction of the audio signal generated in synthesizers from the peak level to sustain level (see the term ADSR). 2) The fade out of the reverberation of a sound

Decibel - The ratio of two Levels according to a scale where a certain percentage change is one unit.

Text Reference: Lesson 17

De-esser - 1) An audio compressor or limiter with its control, circuit made more sensitive to the sounds made by a person pronouncing "s." 2) Any device that will reduce the high frequency energy when "s" is loudly pronounced.

Definition - 1) The quality of a sound that allows it to be distinguished from other sounds. 2) In Lexicon Reverb Units, a parameter which sets a decrease in reverberation density in the later part of the decay.

Degauss - A term with the same meaning as Demagnetize (to remove the magnetism from).

Delay - A signal which comes from a source and then is delayed by a tape machine or delay device and can be mixed with the original (non-delayed) signal to make it sound fuller, create echo effects, etc.

Delay Effects - Any signal processing that uses delay as its basis for processing such as echo, reverb delay and special effects like flanging and chorusing.

Text Reference: Lesson 27

Demo - 1) An inexpensively made recording which gives an idea of some of the musical performances that could be used in a final music production. 2) To make a demo. 3) Any demonstration or trial use of equipment that nay be purchased in the future. 4) The equipment being demonstrated.

Detune - To tune slightly flat, especially when double tracking, usually to give a fuller sound.

D.I. - An abbreviation of the term Direct Injection or Direct Input.

Dialogue - The spoken word recorded in film/video sound, commercials and instructional recordings.

Diaphragm - The part of the microphone, which moves because the pressure changes of the sound pressure wave, move it.

Digital -  Literally "Of Numbers"

Digital Controls - 1) Controls that have changing number displays when the control is changed. 2) Controls that change the digital control signal bits to change the value of some functions.

Digital Delay - A delay line or delay effects unit that converts the audio signal into a digital audio signal, delays it, and converts it back to an analog audio signal before sending it out of the unit.

Digital Domain - In a state of being binary numbers or binary number signals rather than analog or analog signals.

Digital Error - Lost bit information used in the digital words of the digital audio signal.

Digital Interface Format (DIF) - A specification of the number of bits, what the individual bits mean, the voltage, and type of connector for digital audio connections.

Digital Multimeter - A small hand-held, battery operated, testing device that will test voltage, current, and resistance levels as well as continuity, giving a digital display.

Digital Recording - The process of convening audio signals into numbers that represent the waveform and storing these numbers.

Digital Signal Processing - Any signal processing done after an analog audio signal has been converted into digital audio.

Digital To Analog Converter - A device to change digital data numbers that make up the digital audio into discrete voltage levels that approximate the original analog audio waveform.

Digital Word - A number of information bits that will communicate one value; each word being a standard length.

Dip - To reduce the level of signals in a specific band of audio frequencies.

Direct - 1) Using a direct pickup. 2) Using a direct output. 3) Recording all musicians to the final two track master without using a multitrack tape.

Direct Box - An electronic device utilizing a transformer or amplifier to change the electrical output of an electric instrument (for example, an electric guitar) to the impedance and level usually obtained from a microphone.

Direct Current - Electric current flowing in one direction only. Abbreviated DC.

Direct Input - A term meaning the same thing as the term Direct Pick Up (feeding the signal from an electrical output of an electric instrument to the recording console or tape recorder without using a microphone but by changing the electrical output of the instrument to the impedance and level of a microphone).

Direct Injection - Same as the term Direct Pick Up (feeding the signal from an electric instrument to the recording console or tape recorder without using a microphone but by changing the electrical output of the instrument to the impedance and level of a microphone).

Direct Output - 1) On most consoles, an output of the console activated by the direct output switch, which connects a numbered input module to the same numbered track (for example. the direct output on input module one feeds to track one of the tape recorder). 2) On some consoles, a jack that is the output of a console input module and can be used to patch the signal from this module to any tack input of a tape machine.

Text Reference:  Lesson 13

Direct Pick Up - Feeding the signal from an electric instrument to the recording console or tape recorder without using a microphone.

Direct Sound - The sound which reaches a microphone or listener without hitting or bouncing off any obstacles.

Directional Pattern - 1) In microphones, a term meaning the same thing as the term Pick Up Pattern (a description or graphic display of the level that a microphone puts out because of sounds arriving from different directions). 2) In speakers, the pattern of dispersion (the area that the sound from a speaker will evenly cover in a listening area).

Text Reference: Lesson 5

Disk (Disc) - 1) A round flat object (usually housed in a protective sleeve) coated with material that can be magnetized in a similar manner to tape. 2) Any round flat object capable of storing audio signals (digital or analog) or digital data, including phonograph records and compact discs.

Disk Operating System - Full name of DOS (the function of storage and handling of data by the computer).

Distant Micing - The technique of placing a mic far from a sound source so that reflected sound is picked up with the direct sound.

Distortion - 1) The audio garble that can be heard when an audio waveform has been altered, usually by overload of an audio device like an amplifier. 2) The similar garbled sound that can be heard when the sound pressure level is too loud for the waveform to be accurately reproduced by the human hearing mechanism.

Text Reference:  Lesson 11

Diversity - A system in wireless microphone receivers that switches between two or more antennas to prevent dropouts in the audio.

Text Reference:  Lesson 9 - Illustration

Dolby - The name of a manufacturer (and a trademark) of noise reduction systems and other audio systems, to improve performance and fidelity of audio recording, playback, and transmission.

Doppler Effect - A change in frequency of a delayed signal caused by the delay time changing while the cycle is being formed.

DOS - Short for Disk Operating System, which is the function of storage and handling of data by the computer.

Double - 1) To record a second performance, double tracking (recording a second track with a second performance, closely marching the first performance). 2) To use a delay line with medium delay to simulate this.

Drive - 1) To control something else, especially mechanical movement of a recording or playback device. 2) The mechanical mechanism used to Drive (definition 1). 3) To feed a signal to. 4) Short for Disc Drive, the mechanism that writes and reads digital data to and from a floppy disk.

Driver - The unit that feeds a sound pressure wave into the throat of a horn (in a horn loudspeaker).

Text Reference: Lesson 37

Dropout - A very short absence of signal in magnetic recording usually caused by dirt or defects in the magnetic coating of tapes and discs or any very short loss of an audio signal.

Drum Booth (Drum Room) - An isolation booth/room setup for recording a drum set.

Drum Machine - A sample playback unit (or sound module with synthesized sounds) with drum sounds that can be sequenced by an internal sequencer to play drum patterns.

Drum Pattern - A sequence of drum soundings during a tune played by a drummer or sequenced into a drum machine; especially a short pan used in part of a song.

Dry - 1) Having no reverberation or ambience. 2) More loosely used to describe an audio signal without any signal processing.

DSP - An abbreviation for Digital Signal Processing (Any signal processing done after an analog audio signal has been convened into digital audio).

Dub - 1) To copy a recording. 2) A copy of a recording. 3) A recording made in time with another recording so the final result is a mix of the first recording and second recording. 4) To add dialogue to a picture after the picture has been filmed or recorded on video tape

Dynamic Microphone - 1) A microphone in which the diaphragm moves a coil suspended in a magnetic field to generate an output voltage proportional to the sound pressure level. 2) Occasionally used to mean any microphone that has a generating element, cutting magnetic lines of force to produce an output; a dynamic microphone (definition 1) or a ribbon microphone.

Text Reference: Lesson 3 - Illustration

Dynamic Processing (Dynamic Signal Processing) - An automatic change in level (or gain) to change the level relationship of the loudest audio to the softest audio.

Text Reference:  Lesson 16

Dynamic Range - 1) The level difference (in dB) between the loudest peak and the softest level of a tune recording etc. 2) The level difference between the level of clipping and the noise level in an audio device or channel.

Text Reference:  Lesson 16

Dynamics - 1) The amount of fluctuation in level of an audio signal. 2) In music, the playing of instruments loudly or softly at different times.

Text Reference:  Lesson 16

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- E -

Early Reflections - The first echoes in a room, caused by the sound from the sound source reflecting off one surface before reaching the listener.

Earth - The British version of the term Ground (In electronics, a place that has zero volts). 

Echo - 1) One distinct repeat of a sound because of the sound reflecting off a surface. 2) Loosely, used to mean reverberation (the continuing of a sound after the source stops emitting it, caused by many discrete echoes closely spaced in time). 

Text Reference: Lesson 24

Echo Chamber - 1) A room designed with very hard, non-parallel surfaces and equipped with a speaker and microphone. 2) Any artificial or electronic device that simulates the reverberation created in a room. 

Echo Return - An input of the console, which brings back the echo (reverberation) signal from the echo chamber or other echo effects device. 

Text Reference: Lesson 25

Echo Send - The output of a console used to send a signal to an echo chamber or delay effects device. 

Text Reference: Lesson 25

Echo Send Control - A control to send the signal from the input module to the echo chamber or effects device via the echo buss.

Text Reference: Lesson 25

Editing - 1) Changing the sequence of a recording by cutting the recording tape and putting the pieces together in the new sequence with splicing tape. 2) Punching in and then punching out on one or more tracks of a multitrack tape recorder to replace previously recorded performances. 3) Changing the sequence of a digital recording's playback by computer program.

Effects - 1) Various ways an audio signal can be modified by adding something to the signal to change the sound. 2) Short for the term Sound Effects (sounds other than dialogue, narration or music like door closings, wind, etc. added to film or video shots). 

Effects Track - 1) In film production audio, a recording of the mixdown of all the sound effects for the film ready to be mixed with the dialogue and music. 2) In music recording, one track with a recording of effects to be added to another track of a multitrack recording. 

Electret Condenser - A condenser microphone that has a permanently polarized (charged) variable capacitor as its sound pressure level sensor. 

Electric Current - A more formal term meaning the same as the term Current (the amount of electron charge passing a point in a conductor per unit of time).

Electric Instrument - Any musical instrument that puts out an electrical signal rather than an acoustic sound. 

Electricity - Electrical current (the amount of electron charge passing a point in a conductor per unit of time) or voltage (the force pushing electrons to obtain electrical current). 

Text Reference: Lesson 2 - Illustration Page

Electromagnetic Field - Magnetic energy put out because of current traveling through a conductor. 

Electromagnetic Induction or Pick Up - The generation of electrical signal in a conductor moving in a magnetic field or being close to a changing magnetic field. 

Electromagnetic Theory - A statement of the principles behind electromagnetic induction: When a conductor cuts magnetic lines of force, current is induced in that conductor. 

Electronics - 1) On a tape machine, the housing for and the channel circuitry which processes the signal to be fed to the heads, provide bias, and playback. 2) The branch of science dealing with the behavior of electrons/charges in vacuums, gases, semiconductors and special conductors. 

Electrons - Negatively charged particles, which revolve around the center of atoms. The movement of such electrons down a conductor causes electrical current.

Text Reference: Lesson 2 - Illustration

Electrostatic Charge - The excess or deficiency of electrons in a given area. 

Engineer - 1) A technician in charge of a recording session; Also called Recording Engineer. 2) A person with an engineering degree. 3) A person with sufficient experience in the field to be equivalent to the education one would receive earning an engineering degree. 

Envelope - 1) How a sound or audio signal varies in intensity over a time span. 2) How a control voltage varies in level over time controlling a parameter of something other than gain or audio level. 

Equal Loudness Contours - A drawing of several curves showing how loud the tones of different frequencies would have to be played for a person to say they were of equal loudness.

Equalization - Any time the amplitude of audio signals at specific set of frequencies are increased or decreased more than the signals at other audio frequencies.

Text Reference: Lesson 20

Equipment Rack - A cabinet with rails (or free standing rails) that have holes to accept screws at standard spaces and used to house outboard gear.

Error Concealment - Putting replacement information bits into a digital audio signal to replace lost bits when the digital recording or processing system cannot verify whether the lost bits were l's or 0's but can make a good guess by comparing the known bits that were close in position to the lost bits. 

Error Correct - Exact replacement of lost information bits in digital audio. 

Error Detection - The process of discovery that sonic information bits have been lost in digital audio. 

Error Message - A prompt on a computer screen telling the operator that an error has occurred. 

Expander - A device that causes expansion of the audio signal. 

Text Reference:  Lesson 16

Expansion - The opposite of compression; for example, an expander may allow the signal to increase 2 dB every time the signal input increased by 1 dB.

Text Reference:  Lesson 16

Expansion Ratio - How many dB the output signal will drop for every 1dB fall in the input signal below the threshold.

Text Reference:  Lesson 18

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Revised: March 20, 2005

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