Glossary of Audio Terms
ambient sound (ambience) Natural background audio representative of a given recording environment. On-camera dialog might be primary sound; traffic noise, sounds from wildlife and refrigerator hum would be ambient.
bidirectional Microphone pickup pattern whereby sound is absorbed equally from two sides only.
boom Extension arm used to suspend a microphone or camera over sound or subject(s) being recorded. Depending on whether a microphone or a camera is attached, the objective is to keep production gear out of camera's view or to provide a unique angle from which to shoot video.
cardioid The most common type of unidirectional microphone. The pickup pattern resembles a three dimensional heart-shaped figure.
condenser Microphone type, also called capacitor or electret condenser. Requires battery or external power source known as phantom power (+48v DC). Uses change in capacitance created by sound pressure on diaphragm to convert sound into electrical signal and are much more sensitive than dynamic microphones.
decibel (dB) Measure of audio signal strength based on a logarithmic scale measured in volts. Also the unit of measure used for sound pressure level (loudness).
dynamic Microphone type, also called "moving coil." Works much like a loudspeaker in reverse, employing a simple diaphragm, magnet and wire coil to convert sound waves into an electrical signal.
frequency Number of vibrations produced by a signal or sound expressed as cycles per second, or hertz (Hz).
lavaliere Small, easily concealed, unobtrusive and aesthetically pleasing microphone, which is typically attached to clothing for interview settings.
mix Combining sound sources to achieve a desired program balance. Finished output may be mono, stereo or surround.
noise Undesirable video or audio signal interference; typically seen as snow, and heard as hiss or hum.
omnidirectional A microphone that picks up sound from all directions.
phone plug Sturdy 1/4-inch male connector compatible with audio accessories, particularly for insertion of microphone and headphone cables.
pickup pattern Defines a microphone's response to sounds arriving from various directions or angles. [See bidirectional, omnidirectional, unidirectional.]
PZM (pressure zone microphone) Small, sensitive condenser mike attached to a plate. Senses air pressure changes in tiny gap between mike element and plate. Guards against comb filter problems created by surfaces like tables or podiums. Also known as boundary microphones.
RCA plug (phono plug) A popular cable connector for home audio as well as video components. Standard connection for consumer electronics audio/video inputs/outputs.
shotgun Highly directional microphone with long "barrel" designed to pick up a narrow field of sound rejecting off-axis sounds.
soundtrack The audio portion of a video recording, often multifaceted with voiceover, background music, sound effects, etc.
sweetening Post-production process of adding music and sound effects, adjusting the sound mix, or otherwise enhancing a final audio track.
synchronous sound Audio matched to images. When the mouth moves, the words come out in sync.
unidirectional Highly selective microphone pickup pattern, which rejects sound coming from behind while absorbing that from in front. The most common pattern for unidirectional microphone is the cardioid pattern.
voiceover (VO) Narration accompanying picture, heard above background sound or music. Talking typically applied to edited visual during post-production.
windscreen Sponge-like microphone shield, thwarts undesirable noise from wind and rapid mike movement.
wireless microphone Consisting of radio transmitter and receiver; utilizes low-power radio signal for cable-free operation.
XLR (Ground-Left-Right) Three-pin plug for three-conductor balanced audio cable, employed with microphones, mixers and most professional audio equipment.