Glossary – C
Cable – A group of one or more insulated conductors, optical fibers, or a combination of both within an enveloping jacket, typically for transmitting electrical signals of different types.
Cable Assembly – Cable that is ready for installation in specific applications and usually terminated with connectors.
Cable Harness –A grouping of cables or wires used to interconnect electronic systems.
Cable Sheath – Conductive protective cover that is applied to cables.
Capacitor – An electronic device made of two plates separated by an insulator, designed to store electrostatic energy. The capacitor is a key component in condenser microphones, for example.
Capstan – A mechanical part of a magnetic tape recorder that controls the speed of the tape as it passes across the tape heads.
Capsule – Space-travel definitions aside, this is the name given to the part of a microphone that contains the diaphragm and active element, the mechanical structure that converts acoustic sound waves into electrical current.
Carbon Microphone – A microphone that uses carbon granules to convert sound waves to electrical impulses. The carbon element sits between two plates; as sound waves hit the carbon granules, it generates changes in resistance between the plates, affecting the electrical signal.
Cardioid Pattern – A microphone pickup pattern which is most sensitive to sound coming from the front, less from the sides, and least from the back of the diaphragm. So named because the pickup pattern is in the shape of a heart (cardio).
Cascade – To connect or “daisy chain” two mixers so that the stereo mixing busses of the first mixer feed into the stereo busses of the second.
CD – An abbreviation for Compact Disc, or a small optical disk with digital audio recorded on it.
Center Frequency – The frequency of an audio signal that is most affected by an equalizer, either boosting or attenuating the frequency. Drawn graphically, this is the very top or bottom (the “peak”) of the frequency bell-shaped curve.
Chase – The automatic adjusting of the speed of a recorder (or sequencer) to keep time with another recorder.
Channel – 1) An audio recording made on a portion of the width of a multitrack tape, or isolated within a digital audio workstation, usually for the purpose of combining with other channels. 2) A single path that an audio signal travels or can travel through a device from an input to an output.
Channel Path – The complete signal path from the sound source to the multitrack recorder (or DAW). For example, an audio signal that travels from the microphone to the preamplifier, then into a channel strip on the mixing console, then is sent through the outputs into the recorder. This is different from the monitor path, which feeds a mix of signals into monitor speakers or headphones without affecting the recorded signals. (See also “Monitor Path.”)
Chord – Three or more musical pitches sung or played together.
Chord Chart – A shorthand form of musical notation that provides the basic chord changes and essential rhythmic information of a song. Most commonly used by studio session players, rhythm sections or jazz bands to provide the skeletal structure of the song while allowing players room to create their own parts and improvise. While lead sheets typically focus on melody line and chord structure, chord charts display mainly chord changes and rhythm. (See also “Lead Sheet.”)
Chorus – 1) The part of a song that is repeated with the same music and lyrics each time, often containing the main point or hook of the song. 2) A musical singing group with many singers. 3) A delay effect that simulates a vocal chorus by adding several delays with a mild amount of feedback and a medium amount of depth.
Circuit – 1) One complete path of electric current. 2) Similar to definition 1, but including all audio signal paths and components to accomplish a particular audio function.
Click Track – A metronome “click” fed into headphone monitors for the purpose of helping the musicians play in time with the song.
Clip – The distortion of a signal due to overloading an electronic device, so named because the resulting graphic waveform looks like the edges of the waveform have been “clipped.”
Clock Signal – A signal sent by a device within the circuit that generates steady pulses or codes to keep other devices in sync with each other. An example in the music world is sequencing via MIDI. The sequencer sends a clock signal so connected devices will play in time.
Close Miking – A microphone placement technique that places the mic close to the sound source to pick up the direct sound and reject ambient sound.
Coaxial Cable – (abbreviated “Coax”) A two-conductor cable that consists of one conductor surrounded by a shield.
Coincident Miking — A stereo miking technique in which two microphones are placed with their heads as close to each other as possible. This prevents phase cancellation problems in the mix because the distance from the sound to either microphone is the same.
Compander – 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.
Comping – 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.”
Compression – 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”).
Compression Ratio – 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.
Compression Driver – A diaphragm that feeds a sound pressure wave into a horn loudspeaker.
Compressor – 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.
Condenser Microphone – 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.
Console – See “Mixing Console.”
Contact Microphone – 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.
Controller – 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.
Corner Frequency – See “Cutoff Frequency.”
CPU – Abbreviation for Central Processing Unit, the main “brain” chip in a computer (also known simply as “Processor”).
Critical Distance – 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.
Crossfade – 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.
Crossover – 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.”)
Crossover Frequency – The frequency at which the crossover stops sending the signal to one speaker and starts sending it to another.
Crosstalk – The unwanted leakage of an audio signal between two audio channels—for example, overlapping signals between channels on a mixing console, or overlapping audio between two tracks of audiotape.
Cue – In general terms, a cue is the starting point for a piece of music or section of music. Depending on the context, the word “cue” may describe: 1) The point at which a musician or vocalist is supposed to start playing or singing; 2) The audio fed to the musicians through headphones so they can determine when to start playing/singing; 3) A specific location point on the music timeline within a DAW or on the tape; or 4) To set the tape or disc to a certain starting point in the song (“cueing” the tape). A cue can even refer to an entire section of music being used for video production. (Confusing, huh?)
Cutoff Frequency – The frequency in a filter beyond which other frequencies are attenuated.
Cutoff Slope – The rate of reduction of the frequencies beyond the passband of a filter. The slope is described as the number of dB the filter reduces the signal for each octave past the cutoff frequency.
Cycle – One complete expression of a waveform beginning at a certain point, progressing through the zero line to the wave’s highest and lowest points, and returning to the same value as the starting point. One complete vibration or sound wave.