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Glossary of terms for Sound Engineers


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



1)  Abbreviation for alternating current.

2)  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).



Having to do with sound that can be heard by the ears.AcousticsThe behaviour of sound and its study. The acoustics of a room depend on its size and shape and the amount and position of sound-absorbing and reflecting material.


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 and4) 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.



In guitar playing, action refers to how far the strings sit off of the guitar neck. When strings are close to the neck, it is referred to as “Low Action”. When the string sit far above the neck, it is called “High Action”. Guitars with low action are easier to play, but make sure they are not too close, or it could causing buzzing.


Active Crossover

Uses active devices (transistors, IC’s, tubes) and some form of power supply to operate.


Active/Inactive Microphones

Scientific definitions aside, active microphones generally sound better than inactive ones, but they generally cost more. They also require the use of either a battery or phantom power while inactive mics need only be plugged into the mic cord in order to work. In most playing situations, the subtle improvement in sound quality from an active mic isn’t worth the extra cost and hassle. One possible exception it the headset mic. Put simply, inactive headset mics just plain suck. Active headset mics put out a much stronger signal and feed back much less.



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.



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



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.



An abbreviation of Audio Engineering Society.



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



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.



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.



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).


Amplifier (Power amp, Head)

It’s the part of the sound system that actually magnifies or “amplifies” the sound. In other words, it makes stuff louder.



The unit of current, abbreviated Amp.



An increasing of signal strength.



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



Sound equipment that converts the low voltage, low current signal from a tape deck, mixer etc. into a higher current signal suitable for driving speakers. See Power Amplifier, Crossover.



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



The strength of a vibrating wave; in sound, the loudness of the sound.



The extreme range of a signal. Usually measured from the average to the extreme.


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.


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.



The visible sparks generated by an electrical discharge.


Attenuator (Pot)

The electronic dohickey under the knobs that increases or reduces the strength of the signal running through it. When these get old and dirty, they can make popping noises or rumbles in your PA (As in “my pots are dirty”).Assign Tochoose 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.



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



The rate the sound begins and increases in volume.



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



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


Automatic Gain Control (Automatic Volume Control)

A compressor with a very long release time used to keep the volume of the audio very constant.



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.


Auxiliary Equipment

Effects devices separate from but working with the recording console.

Auxiliary Input or ReturnA route back into the sound desk for a signal sent to a piece of outboard equipment via an auxiliary send.


Auxiliary Output or Send

An additional output from a sound desk that can be used for foldback or monitoring without tying up the main outputs. Each input channel will have a path to the Aux buss. Also used for feeding a signal to an effects processor. See Auxiliary Return.



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.


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



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.



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.


Balanced input/output

A “balanced” connection is one that has three wires to move the signal. One is a ground, and the other two (called conductors) carry signals of equal value. This is why they are called balanced. Low Z cables and connections are the most common example.



1) The depth and thickness of a sound, usually on the bottom end of the EQ (as in “needs more balls”).

2) The strength of the voice on the mic (as in “check it like you have some balls”).


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.



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



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.



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.



1) The lower range of audio frequencies up to approximately 250 Hz.

2) Short for Bass Guitar.

3) Lower end of the musical scale. In acoustics, the range (below about 200 Hz) in which there are difficulties, principally in the reproduction of sound, due to the large wavelengths involved.

4) The lower frequencies.

5) On the soundboard this should refer to the bass guitar channel, not the bass drum.

6) The lowest frequencies of sound. Bi-Amplification uses an electronic crossover or line-level amplifiers for the high and low frequency loudspeaker drivers.


Bass Roll Off

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



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 BPM

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



A prefix meaning two.



1) A way of optimizing the efficiency of a speaker system by separately amplifying the High Frequency (HF) and Low Frequency (LF) portions of the sound signal and sending them down two pairs of cables to the speaker. Multipin Speakon connectors have been developed to do this.

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


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.



A numbering system based on two. In binary there are two symbols used (“l” and “0”).



The smallest unit of digital information representing a single “0” or 1.



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.



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.


Boom Stand

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



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



The bass frequencies (as in “needs more bottom end”).


Boundary Mic

A microphone mounted on a flat plate that acts as a reflective surface directing sound into the mic capsule. Used for general pick-up over a large area. See PCC, PZM.



The bridge assembly, or just “bridge” is an area on the face of the guitar where the string meet or are connected to the face.



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.



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).



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.



A grouping of eight information bits.