C

cent: The smallest conventional unit of pitch deviation. One hundred cents equal one halfstep. In an instrument, a cent is a term used in discussing pitch resolution; one cent is good, more than six cents is bad. See half-step.

center detent: A notched position in the range of a variable control, allowing the user to return the control to precisely that position, such as the midpoint between the left and right channels in a balance control. Use to denote the flat position on tone controls, etc.

center frequency: The frequency that is boosted or attenuated most by the operation of any parametric equalizer or other similar processing device or circuit. See Q.

center tap: In a transformer, the electrical midpoint of the windings, made accessible for external connection. Used, for example, in delivering power to balanced line condenser microphones. See phantom power, Appendix B.

C-format: The international standard format for professional 1” videotape equipment. Developed by Sony, and sometiines called S-format after that company’s name. See B-format,

Betacam, VHS.

CG: Computer Graphics.

chain: Also called iron. An integrated system composed of separate audio and/or video recording, processing, or playback circuits and/or devices which are used in conjunction with one another to produce one output result. See B-chain, program chain, signal chain, side chain.

change-over dots: See projection.

change-over projection: See projection.

channel: An independently processed or recorded signal. (1) An electrical signal path. In analog audio (such as a mixer), each channel consists of separate wired components. In the digital domain, channels may share wiring, kept separate through logical operations. (2) A system for independently addressing up to sixteen separate MIDI devices over a single MIDI cable. MIDI provides definitions for 16 channels which transmit not audio signals, but digital control signals for triggering synthesizers and other devices. MIDI data are associated with a particular channel by virtue of a Channel ID Number that is interwoven with other MIDI data being recorded. A track holds data that (depending on the sequencer) may or may not be restricted to one MIDI channel. MIDI’s 16-channel limitation has been overcome by employing multiple independent MIDI ports that each route sixteen channels, offering the possibility of hundreds of channels. (3) The left or right signals of a stereo audio system, or the left, right, center, surround and/or subwoofer signals of a multichannel system, such as LCRS or 5.1. (4) In film, A complete, self-sufficient recording setup. A production channel would include a recorder, mixer, microphones, headsets, etc. A transfer channel would include a 1/4” tape deck, a 35mm mag recorder, a resolver, and a monitoring system.

channel assignment matrix: In a recording console, the group of buttons or switches by which the signal from any input channel can be assigned to one or more busses, and thereby be sent to one or more tracks of the multitrack recorder.

C

channel bit rate: The actual bits being read from a digital medium are greater than the number strictly required to encode the audio signal. This is because of ECC and synchronization bits, etc. For example, with a CD, the audio bit rate is 1.41Mbps, but the channel bit rate is actually three times as high, 4.32Mbps.

channel insert: An insertion point in a mixer channel which opens up the signal path and allows an outboard device to be inserted in-line. The output point (the place where the signal is routed to the outboard device) is called the channel insert send, and the place where the effected comes back into the mixer is called the channel insert return. The actual point at which the channel signal path is broken with the insert connection is not standard among all consoles. Some are between the preamp and equalizer sections, some after the equalizer, but before the fader, and some are post-fader. Some are switchable with an internal jumper or other modification. If, for example, the channel insert send is post-fader, the fader setting will affect the action of a compressor that is inserted into the channel’s signal path. On the other hand, a post-fader insert is good when it is desirable to send a single channel’s signal direct to a tape track, making the fader into a convenient record-level control. See normalled connection.

channel message: A class of MIDI messages which only affect devices on a MIDI network set to a particular channel, i.e., all non-system messages. Channel messages may be of either Channel Mode or Channel Voice type. See MIDI.

channel mode: See MIDI mode.

channel path: The record section of the signal chain in a mixer. See also monitor path.

channel pressure: A type of MIDI channel message that is applied equally to all of the notes on a given channel; the opposite of poly pressure, in which each MIDI note has its own pressure value. Also called aftertouch, channel pressure is generated on keyboard instruments by pressing down on a key or keys while they are resting on the keybed. Also called channel key pressure.

channel separation: Channel separation refers to the amount of crosstalk between the channels of a stereo system. It is the inverse of interchannel crosstalk, as measured in decibels. A small amount of crosstalk is equivalent to a large channel separation.

channel strip: One of multiple identical sections in a mixer from the mic preamp and phantom power (if present) to the bus outputs, and typically includes the input pad, EQ, and signal routing, including pan, effect sends and effect returns, and main channel fader, and optionally an automation interface. There is one channel strip per mixer input.

Channel Voice: A classification of MIDI channel message relating specifically to a musical performance, where features of the performance (notes, articulation, etc.) are individually described by a unique message. Channel Voice messages include Note On, Note Off, Polyphonic Key Pressure, Channel Pressure, Program Change, Pitch-bend, and Controller Change. These messages all include a specific channel number, allowing similar messages to address different devices on the same MIDI network. The message will only be implemented by a receiving device whose channel number matches that of the message.

channelize: See MIDI mapping.

C

characteristic impedance: See termination.

charge (C): Charge is a measure of the quantity of electricity and its unit is the coulomb. In an electrical circuit, charge consists of negative charges, or electrons. A positive charge can be thought of as simply an absence, or deficiency of electrons. Charge is what is moving in an electric current. See ampere.

chart: (1) A musical score or arrangement. The term is used both to designate the conductor’s full score, or any band part. (2) A list of current hit singles or albums.

chase: (1) The process whereby a slave device attempts to sync to a master clock. (2) In MIDI parlance, to chase means, upon playback, to look backward to earlier MIDI events to see if there were any program or channel change messages prior to the playback point which would affect playback. See controller chasing.

chase-lock: A type of controller for a video or audio recorder that will listen to the SMPTE timecode signal from the master clock device and will adjust its own speed to find the correct time and then will lock into synchronization with the external timecode. Unlike sync-lock, chase-lock controllers respond to changes in timecode sequence.

chasing: See controller chasing.

chassis ground: The practice of connecting the signal ground of a device to the rack rails or other common grounding location on a multi-component electronic system.

chatter: When the input signal level to a noise gate hovers near the threshold level, the gate may be unsure if it should be open or closed. It may rapidly open and close, resulting in the audio cutting in and out; this is known as the gate “chattering.” To correct this problem, adjust the threshold setting to be slightly lower or higher.

checksum: A number derived from arithmetical actions on data, used to check that data has not been corrupted after transmission or recording and replay.

chip: (1) In vinyl record production, the thin thread of acetate lacquer that is carved out of the master disc by the cutting stylus. Also called swarf. (2) A slang term for integrated circuit.

chirping: An effect caused by the overuse of single-ended noise reduction systems whereby the low-level signals take on an electronic, “ringing” character, known as chirping. If the signal is very noisy, the noise floor itself begins to sound chirpy, which can be more annoying than the original, broad-spectrum, noise.

chord: The playing of multiple notes simultaneously. The opposite of an arpeggio. See inversion.

chorus: (1) A regularly repeated section of a song or other musical composition. (2) A group of singers, also called a choir.

C

chorusing: A type of audio effect in which a delayed (30-40ms) or detuned copy of a signal is mixed with the original signal. The mixing process changes the relative strengths and phase relationships of the overtones to create a more complex sound. See ADT, double-tracking. The mixture becomes extremely complex as the relative phases of the signals cause partial cancellation and reinforcement over a broad frequency spectrum. The simplest way to achieve chorusing is to detune one synthesizer oscillator from another to produce a slow beating between them. See comb filter.

chromatic: Pertaining to the full twelve-note scale, as opposed to the eight-note diatonic scale.

Cinema Digital Sound (CDS): A new system of digitally recording motion picture sound format introduced by the Optical Radiation Corporation, a division of Kodak, in 1990, for the film “Dick Tracy” for digital sound on 35mm or 70mm film formats via a laser beam, which reportedly combines the dynamic and frequency ranges and low distortion of the CD on six discrete channels. Five channels encompass the full audio bandwidth and the sixth is designated a subwoofer channel, containing only the lowest frequencies. The CDS-encoded film is capable of being shown with conventional stereo optical sound, but requires a special sound system to reproduce the six channels digitally. First used in 1990, this format lasted only two years and is now obsolete. See AC-3, 5.1.

CinemaScope: The trademark of a widescreen camera system developed by Twentieth Century Fox, the first true stereophonic motion picture sound system which had the soundtracks on the same film with the picture. First used in 1953, CinemaScope was responsible for popularizing the anamorphic film format.

Cinerama: A widescreen system comprising three 35mm cameras/projectors running in interlock with 7-track mag film.

CIRC: Cross Interleaving Reed-Solomon Code. The combined error detection and correction scheme used in CDs. See interleaving.

C

Circle of Fifths: Also known as the Cycle of Fifths. A way of thinking of the twelve major and minor keys as a circle, arranged in steps of a fifth, which can be read in either direction. Starting from Cmaj and proceeding clockwise, the key signature of each new key gains one

sharp until Fmaj is reached. At that point, F becomes Gmaj and the cycle continues, removing a flat at each step until back to C. If one goes counter-clockwise, the circle is a series of perfect cadences, with each new tonic key becoming the dominant of the next. For this reason, the Circle of Fifths is often used for modulation(3), especially to or back from a remote key, i.e., a key on the far side of the circle.

		F =G
	B	D
	E	A
A	Circle of Fifths E
	D	B
	G	F
		C

circuit: A complete path that allows electrical current from one terminal of a voltage source to the other terminal.

circumaural: A headset with a large cushion which surrounds the ear to exclude external noise, unlike supraaural or intraaural designs.

CIT: See SDMI.

clangorous: Containing partials that are not part of the natural harmonic series, i.e., partials which are not whole-number multiples of the fundamental frequency. Clangorous tones often sound bell-like.

clef: In written music, a symbol placed at the beginning of the stave which assigns a pitch to a specific line on the stave, and by inference, to all of the other lines and spaces. Three clef

symbols are commonly used, derived from the medieval forms of the letters G ( ), F( ), and

C( ).