Audio Glossary

 

A rundown of the basic terminology  associated with audio

Ad-lib

Unrehearsed, spontaneous act of speaking, performing, or otherwise improvising on camera without preparation.

AGC

(Automatic gain control) A circuit on most camcorders that automatically adjusts a

microphone’s gain (volume) to match environmental sound levels.

Ambient sound

(Ambience) Natural background audio representative of a given recording

environment. On-camera dialog might be primary sound; traffic noise and refrigerator

hum would be ambient.

Amplify

To magnify an audio signal for mixing, distribution and transducing purposes.

Audio dub

Result of recording over pre-recorded videotape soundtrack, or a portion thereof,

without affecting pre-recorded images.

Audio mixer

The piece of equipment used to gather, mix and amplify sounds from multiple

microphones and send the signal on to its destination.

Backing Track:

Pre-recorded accompaniment for a singer or voiceover actor who then listens through headphones to a replay as he/she performs. Generally, the two signals are ultimately mixed to produce the final recording.

Dubbing

An actor’s voice synchronization with lip movements which are not the originally recorded sound. This is used to replace unusable dialogue or recordings.

Boom, microphone

Any device for suspending a microphone above and in front of a performer.

Condenser mic

A high-quality mic whose transducer consists of a diaphragm, back plate and

capacitor.

Decibel

(dB) A unit of measurement of sound that compares the relative intensity of different

sound sources.

Digital audio

Sounds that have been converted to digital information.

Equalize

To emphasize, lessen or eliminate certain audio frequencies.

Feedback

Echo effect at low levels, howl or piercing squeal at extremes, from audio signal being fed back to itself.

Frequency

The number of times a signal vibrates each second as expressed in cycles per second (cps) or Hertz (Hz).

Gain

The ratio of the signal level at the output of an audio device to the signal level at its input. Expressed in decibels (db)

Handheld mic

A microphone that a person holds to speak or sing into.

Hi-fi

(High fidelity) Generalized term defining audio quality approaching the limits of human

hearing, pertinent to high-quality sound reproduction systems.

High-Pass Filter

An electronic filter used to attenuate all frequencies below a chosen frequency.

Hiss

Primary background signal interference in audio recording, result of circuit noise from

a playback recorder’s amplifiers or from a tape’s residual magnetism.

Impedance

Opposition to the flow of an audio signal in a microphone and its cable.

Input channel

On an audio board, the control into which a microphone, tape recorder or other source is plugged.

Lapel mic

A small mic often clipped inside clothing or on a tie or lapel.

Lip sync

Proper synchronization of video with audio — lip movement with audible speech.

Lowpass Filter

A filter that attenuates frequencies above a specified frequency and allows those below that point to pass.

Master fader

The audio volume control that is located after all the input channel controls and after

the submaster controls.

Mic

(also “mike”) short for microphone.

Mix

Combining sound sources to achieve a desired program balance. Finished

output may be mono, stereo or surround.

Nonsynchronous sound

Audio without precisely matching visuals. Usually recorded separately, includes wild

sound, sound effects, or music incorporated in post-production.

Omnidirectional

A microphone that picks up sound from all directions.

Phantom Power

A method of remotely powering the preamplifier which is built into many microphones by sending a voltage along the audio cable.

Phone plug

Sturdy male connector compatible with audio accessories, particularly for insertion of

microphone and headphone cables. Frequently referred to by their sizes, usually 1/4-

inch and 1/8-inch. Not to be confused with phono plug.

Phono plug

(RCA) Shrouded male connector used for audio and video connections. Frequently

referred to as RCA plugs, they only come in one size. Not to be confused with phone

plugs.

Pickup pattern

Defines a microphone’s response to sounds arriving from various directions or

angles.

Preamp

An electronic device that magnifies the low signal output of microphones and other

transducers before the signal is sent to a mixing board or to other amplifiers.

PZM

(Pressure zone microphone) Small, sensitive condenser mic, usually attached to a

metal backing plate. Senses air pressure changes in tiny gap between mic element

and plate.

RF

(Radio frequency) Combination of audio and video signals coded as a channel

number, necessary for television broadcasts as well as some closed-circuit

distribution.

RF converter

Device that converts audio and video signals into a combined RF signal suitable for

reception by a standard TV.

Shotgun

A highly-directional microphone used for picking up sounds from a distance.

Sound bite

Any short recorded audio segment for use in an edited program — usually a highlight

taken from an interview.

Sound effects

Contrived audio, usually pre-recorded, incorporated with a video soundtrack to

resemble a real occurrence. Blowing on a microphone, for example, might simulate

wind to accompany hurricane images.

Soundtrack

Generically refers to the music contained in a film, though it literally means the entire audio portion of a film, video or television production, including effects and dialog.

Stereo

Sound emanating from two isolated sources, intended to simulate pattern of natural

human hearing.

Sweetening

Post-production process of adding music and sound effects or otherwise enhancing

the existing audio with filters and effects.

Synchronous sound

Audio recorded with images. When the mouth moves, the words come out.

Underscore

Music that provides emotional or atmospheric background to the primary dialog or narration onscreen.

Unidirectional

Highly selective microphone pickup pattern, rejects sound coming from behind while

absorbing that from in front.

Voiceover

(VO) Audio from an unseen narrator accompanying video, heard above background

sound or music. Typically applied to edited visuals during post-production.

VU Meter

A meter, often in editing software, designed to measure audio level in volume units which generally correspond to perceived loudness.

White noise

A signal having an equal amount of energy per hertz, usually sounds horrible!

Wild sound

Nonsynchronous audio recorded independent of picture ie. rain on roof, five o’clock

whistle — often captured with separate audio recorder.

Windscreen

Sponge-like microphone shield, thwarts undesirable noise from wind and rapid mic

movement.

Wireless mic

A microphone with a self-contained, built-in miniature FM transmitter that can send the

audio signal several hundred feet, eliminating the need for mic cables.

XLR

(Ground-left-right) Three-pin plug for three-conductor “balanced” audio cable,

employed with high-quality microphones, mixers and other audio equipment.