A signal processor serving as a combination compressor and expander, primarily used for noise reduction purposes in analog systems. The audio signal is compressed prior to recording, then expanded at the reproduction stage. Companding is the principle behind Dolby noise reduction systems.
1) In digital audio workstations (DAWs), the process of blending portions of multiple recorded takes to create a “compliation” track. (See also “Take,” “Playlist.) 2) In jazz music performance, an abbreviation for “accompanying.”
1) In signal processing, the action performed by a compressor (see also “Compressor”). 2) In acoustics, the increased air pressure caused by the peak of a sound pressure wave, used in the context of “compression and rarefaction” (see also “Rarefaction”).
A diaphragm that feeds a sound pressure wave into a horn loudspeaker.
The rate by which a compressor attenuates an incoming signal, measured in decibels. For example, a compression ratio of 4:1 means the compressor will only allow a 1 dB increase in the signal for every 4 dB increase in the signal above the threshold.
A signal processor or plug-in that reduces the dynamic range of an audio signal by amplifying its quieter sections and attenuating its louder ones.
A microphone in which sound is converted into electrical current through changes in a capacitor. The sound pressure waves move the diaphragm, producing changes in capacitance which are then changed into electrical voltage.
See “Mixing Console.”
A microphone designed to pick up vibrations from solid objects (as opposed to vibrations in the air). Also known as a “pickup” or “piezo,” this microphone is often used as an acoustic guitar pickup to pick up the vibrations from the soundboard, or by experimental musicians creating “noise music” from a variety of objects.
In the broadest sense, a controller is any device that is used to control another device. Most commonly used in the context of MIDI controllers, which send out MIDI signals to control other connected MIDI instruments and devices. Other examples of controllers in the recording studio can include monitor controllers, DAW controllers and DJ controllers.
See “Cutoff Frequency.”
Abbreviation for Central Processing Unit, the main “brain” chip in a computer (also known simply as “Processor”).
The distance from the sound source at which the direct sound and the reverberant sound are at equal volume. Critical distance varies according to the space; in a room with absorbent walls, the critical distance will be further from the source, and in a reverberant room, the distance will be closer to the source.
An audio editing technique in which one sound is faded out as another sound is faded in, to create a seamless transition between the two. Audio engineers use crossfading, for example, to blend two takes or more “takes” of a recorded track into a composite take. Club DJs also use crossfading to transition from one song to the next with no stops.
An audio filter component that splits an audio signal into two or more bands or signals, usually to be fed into different components of a loudspeaker system according to frequency range. (Also called a “crossover network.”)
