Glossary – Studios

A-D Converter:
Short for Analogue / Analog to Digital Converter. Changes a continuously varying electrical signal into a stream of binary data.

Audio Engineering Society / European Broadcast Union. Digital audio transfer standard, similar to S/PDIF. Uses 3 pin XLR connectors.

Automatic Gain Control. Circuitry within recording equipment which compensates for differences in volume in the incoming sound signal by adjusting the gain automatically. Helps to reduce wild swings in volume.

Electronic equipment that increases strength of signals passing through it

Analogue Signal:
An analogue recording will record the exact waveform of the original sound, simply converting it to an electrical signal at the microphone, and back into air movement at the speaker.

To reduce the intensity of a signal.

Facility available on larger sound mixing desks allowing channel muting or even fader moves to be taken under the control of a computer to ensure accurate and repeatable mixing. Radio programmes can also be recorded onto computer harddisks and played out automatically, this form of broadcasting is called automation.

Auxiliary Input or Return:
A route back into the sound desk for a line level signal sent to a piece of outboard equipment (usually effects processor / EQ unit etc.) via an auxiliary send.

Auxiliary Output or Send:
An additional line level output from a sound desk which 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.

Balanced Line:
A method of carrying sound signals which reduces interference by using a third conductor, the shield. In the balanced line the shield, which is grounded, is in addition to the two signal-carrying conductors. Balanced lines are less prone than unbalanced to interference. In balanced lines, one of the signal wires carries the audio signal, while the other carries an out-of-phase (inverted) copy. When the signal reaches the destination, the inverted copy is flipped and added to the original. Any noise added by interference is also inverted. When combined with the non-inverted noise, the two noise signals cancel each other out.

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

Hardly used now, but these tapes were used to record jingles and ads onto and comprised of a continuous loop of tape in a plastic box that when played always came back to the start ready for the next time it was needed.

Abbreviation for compact disk, a device to store audio recordings on.

Clean Feed:
A supply that is free from interference from other equipment.

Used to compress an audio signal so that it conforms within desired parameters.

A leakage between two audio circuits.

The command given to carry out a particular operation such as to prepare something to start. For example cue up a song to the beginning of the track.

Distribution Amplifier. Splits and Amplifies an audio source.

Abbreviation for digital audio tape, a device to store audio recordings on.

Usually undesirable result of overloading sound equipment. Reducing the levels can remedy the situation.

The process of adjusting the tonal quality of a sound. A graphic equaliser provides adjustment for a wide range of frequency bands, and is normally inserted in the signal path after the mixing desk, before the amplifier.

Slideable button found on a mixing desk for altering the audio loudness.

A power supply to a piece of equipment or installation is termed a “feed”. Sound equipment and sensitive computer equipment should have a clean feed – that is, a supply that is free from interference from other equipment. A signal from one system to another is also known as a feed (for example, an audio signal from a sound desk of a concert back to the radio station is known as a feed.)

A loud whistle or rumble heard emanating from a sound system. It is caused by a sound being amplified many times.

IDC (Insulation Dependent Connector):
IDC’s are designed to be connected to the conductor of an insulated wire by a connection process which forces a blade or blades through the insulation, removing the need to strip the wire before connecting. Punchdown blocks are intended to take individual wires punched down into each position in the block with a special tool.

Abbreviation for Integrated Services Digital Network, a high quality line used to transmit data, voice, and video in digital high quality.

Segmented audio connector. Mono Jacks have two connections – tip and sleeve, and are unbalanced. Stereo jacks have three connections – tip, ring and sleeve. B-type jacks (also known as Bantam jacks) were originally designed for use in telephone exchanges and provide a high quality (and expensive) connection in jackfields. A-type jacks are cheaper and more common, but more fragile. A type jacks are available in 2 sizes : quarter inch and eighth inch.

Junction box where different audio signals are terminated. Used to re-route audio to different pieces of equipment or to different parts of a building. Usually located in the studio desk or in the racks room, or both.


A device to limit an audio signal if the volume level is too high. Large volume levels can either damage sensitive equipment or can sound distorted when listened to on air.

Line Level Signal:
“Standard” level at which the inputs and outputs of domestic and professional sound equipment operate. Slight variations are that some equipment works at +4dB, some at -10dB.

Line-up Tone:
Signal of known frequency and level used for setting up sound recording equipment levels accurately.

All stations in England are required to record their output for a minimum of 42 days. This recording is called logging.

A device comprising a number of input channels where each sound source is provided with its own control channel through which sound signals are routed into two or more outputs. Many mixing desks can also change the quality of the sound.

Mono (Monophonic):
Single channel sound recording, as opposed to Stereo (Stereophonic), which uses two channels (left and right).

Phantom Power:
Some condenser microphones require a power supply in order to operate. If this supply is not from a battery within the microphone body, it is known as a phantom power supply. It is usually 48 Volts DC, and is supplied either by a separate battery pack, or by the mixer. The supply is termed “phantom” because it is “invisibly” carried down the same microphone cable as the sound signals.

Two identical sound waves which are slightly apart in time are said to be out of phase; two identical waves are in phase.

Abbreviation for peak programme meter’s, used on audio equipment to show the loudness level of audio.

Pre-fade Listen (PFL):
Control on a mixing desk which allows the user to check the presence of a signal, and its quality before bringing up the fader.

An output from a sound desk is said to be prefade if it is independent of the channel fader.

Signal To Noise Ratio:
The ratio, usually expressed in decibels, of the average signal (recorded or processed) to the background noise (caused by the electronic circuits).

Stereo (Stereophonic):
Reproduction of sound using two or more independent audio channels in such a way as to create the impression of sound heard from various directions.

Talk Back:
System employed within studios or on outside broadcasts where by two different people can talk to each other without it being broadcast.

Abbreviation for volume unit, used on audio equipment to show the loudness level of the audio.

Multipin audio connector. The UK standard for wiring the 3 pin connector is as follows : Pin 1 (Screen), Pin 2 (+ve / “hot”), Pin 3 (-ve, “cold”). (Xternal, Live, Return).