Music and Audio Glossary of Terms—Part 1

The modern world is full of three-letter acronyms, or TLAs, and other jargon. The world of music and audio is no different.

Every given topic area has its own specific abbreviations and terminology that can, at first, be impenetrable to some. In this tutorial I attempt to demystify a few of the terms that you’re likely to read in our tutorials.

Aa

ADC—Analogue to Digital Convertor

An ADC, or Analogue to Digital Convertor, is a device that converts an analogue signal into a digital signal.

These days, audio information is often stored digitally. Think mp3 player. In order to record the information to a computer, the analogue information from a microphone needs to be converted into a digital signal.

ADR—Automated Dialogue Replacement

Automated Dialogue Replacement, or ADR, is a process whereby dialogue that is unclear on production soundtracks is unclear or unusable for another reason. The sound is re-recorded by the actor in a process known as looping. 

The actor will watch the scene repeatedly and re-record the necessary dialogue attempting to gain clarity, the right emotion and syncing their wording with the movement of their mouth and lips on the film.

Amp—Amplifier

An amplifier, or amp as it is often called, is an electronic device that increases the power of a signal. It functions by taking and controlling power from a power source and outputs it to match the input signal but with a larger amplitude.

The amplifier essentially modulates the the output of a power supply based upon the shape of the input signal. An amplifier provides gain.

An amplified waveform
An amplified waveform (reproduced under Creative Commons CC0 1.0 Universal licence)

Attenuator

An attenuator is an electronic device that is used to reduce the amplitude, or power, of a signal without causing distortion to its waveform.

Where an amplifier provides gain, an attenuator provides loss. Technically speaking, an attenuator also provides a gain of less than one.

Generally, attenuators are passive devices that are made using voltage dividers and supresses, rather than opposes, a frequency. An attenuator can be used for filtering and for noise-reduction.

Bb

Bus

A bus is a term that is used to describe any type of audio conduit that permits a number of different signals to be routed and/or processed together.

In its simplest terms a bus is the pathway along which an electrical signal flows. For example, the output of a sound mixer is referred to as the master stereo bus.

You can feed the chosen signals into the bus, process the mixed signal if required and feed the signal to a chosen destination.

In terms of digital audio workstations, or DAWs, the term mix bus is normally given to the output channel. A drums bus would be a mixer channel that collects all of the signals from microphones on the drums, for instance.

Cc

Channel

A channel is similar to a bus in that it is a pathway through an audio device. 

In audio and sound, the term channel specifically refers to an individual audio track. When referring to more than two channels it is called multichannel.

For example, sound mixers have multiple input channels.

Compression

Compression means one of two things. It’s a method of reducing the size of a digital file. In audio terms it’s usually a method of evening out the dynamic range of a signal.

Also referred to as DRC, or Dynamic Range Compression, compression is signal processing that reduces the volume of loud sounds or amplifies quiet sounds by compression an audio signal’s dynamic range.

Compressors used to be separate electronic hardware units. Since the turn of the century, compressors have become widely available as software plugins for popular DAW software.

Console

A console, or mixing console, is an electronic device for combining, routing and changing the properties and dynamics of multiple audio inputs.

For example, a mixing console can change the volume level and timbre, or tone, of microphone inputs of vocalists, instruments or electronic inputs from electronic instruments such as electric guitars and synthesisers.

Consoles are also referred to as Mixers.

Dd

DAW—Digital Audio Workstation

A digital audio workstation is an electronic device or, often, a software app for recording, editing and producing audio files.

A DAW can be a program on a laptop, an integrated standalone electronics hardware unit or a highly-complex configuration of many components controlled by a central computer.

Whatever the configuration, a DAW has a central interface that allows the user to mix multiple tracks and recordings into a final piece.

The design of DAWs is generally based upon that of a multitrack tape recorder, a metaphor that makes it easier for musicians and recording engineers who are already familiar with using tape recorders.

Delay

In music and audio, delay can mean:

  1. The postponement of an audio signal for a specific amount of time, usually measured in milliseconds, or
  2. A device designed to delay an audio signal

Either way, delay is an audio effect that records an input signal to an audio storage medium and plays it back after a short amount of time, normally measured in milliseconds.

The effects of delay can range from subtle echo effects to densely overlaid textures of notes with complimentary rhythms favoured by singers and instrumentalists seeking to add an ethereal quality to the sound.

Extremely long delays can be used to create the repetition of musical phrases or tape-loops.

Decibel (dB)

A Decibel, abbreviated to dB, is a logarithmic unit of measurement the express the ratio of two values of a physical quantity. One of the values is often a standard reference to which decibel is used to express the other value relative to the reference.

In audio terms, dB is used as a unit of sound pressure level.

A suffix of often appended to the dB unit to indicate the reference value by which the ratio is calculated. 

An example is dB SPL, meaning Sound Pressure Level, referenced to the nominal threshold of human hearing. Silence (as far as the human ear can tell) is expressed as 0dB, whispered speech is 20-30dB, an average conversation is 60-70dB a rock concert is around 110dB and is enough to cause hearing loss after only 15 minutes or so.

DAC—Digital to Analogue Convertor

A DAC, or Digital to Analogue Convertor, is a device that converts a digital signal into an analogue signal.

These days, audio information is often stored digitally. Think mp3 player. In order to be heard through speakers, the digital information needs to be converted into an analogue signal.

DRC—Dynamic Range Contol

See Compression.

Distortion

Distortion is the alteration of the shape of a waveform. It’s usually unwanted and sound engineers strive to eliminate distortion. That said, distortion can be used as a musical effect, particularly with electric guitars.

In this case, distortion is a form of audio processing used to alter the sound from electric musical instruments and is often achieved by increasing their gain.

Distortion can be created using effects pedals, pre-amps, speakers and, latterly, through digital audio software.

Dynamic Range

Dynamic range is a measurement of the difference between the quietest possible sound (silence) and the loudest possible sound that can be handled by a given medium. 

The potential dynamic range of music in an acoustic environment is as high as 120dB. The dynamic range of a CD is closer to 80dB, FM radio is only about 50dB and AM radio a mere 30dB. 

With these severe limitations on dynamic range, compression becomes necessary in order to allow the changing dynamics in music to be heard.

DSP—Digital Signal Processor

A DSP, or Digital Signal Processor, takes a signal such as a voice or music track that has been digitised and then mathematically manipulates it.

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