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HOME THEATER'S AV GLOSSARY

C

Cascading Crossovers: Two crossovers used in series on the same signal in the same frequency range causing greater attenuation of the out-of-band signal. For example, using the crossover in a receiver's bass management setting and the one in a subwoofer simultaneously will create an exaggerated loss of signal.
Cathode Ray Tube: (CRT) Analog display device that generates an image on a layer of phosphors that are driven by an electron gun.
CD: Compact Disc. Ubiquitous digital audio format. Uses 16-bit/44.1-kHz sampling rate PCM digital signal to encode roughly 74 or 80 minutes of two-channel, full-range audio onto a 5-inch disc.
CD-R: Recordable Compact Disc
CD-RW: Rewritable Compact Disc
CEA: Consumer Electronics Association. An association of manufacturers of consumer electronics products.
Center Channel: The center speaker in a home theater setup. Ideally placed within one or two feet above or below the horizontal plane of the left and right speakers and above or below the display device, unless placed behind a perforated screen. Placement is important, as voices and many effects in a multichannel mix come from this speaker.
Channel: In components and systems, a channel is a separate signal path. A four-channel amplifier has at least four separate inputs and four separate outputs.
Chrominance: (C) The color portion of a video signal.
Coaxial:1) A speaker typically with one driver in the middle of, and on the same axis as, another driver. 2) An audio or video cable with a single center pin that acts as the hot lead and an outer shield that acts as a ground.
Codec: Mathematical algorithms used to compress large data signals into small spaces with minimal perceived loss of information.
Coloration: Any change in the character of sound (such as an overemphasis on certain tones) that reduces naturalness.
Component Video: A signal that's recorded or transmitted in its separate components. Typically refers to Y/Pb/Pr, which consists of three 75-ohm channels: one for luminance information, and two for color. Compared with an S-video signal, a Y/Pb/Pr signal carries more color detail. HDTV, DVD, and DBS are component video sources, though most DBS material is transcoded to component from composite signals.
Compound Loading: See Isobarik.
Composite Video: A signal that contains both chrominance and luminance on the same 75-ohm cable. Used in nearly all consumer video devices. Chrominance is carried in a 3.58-mHz sideband and filtered out by the TV's notch or comb filter. Poor filtering can result in dot crawl, hanging dots, or other image artifacts.
Contrast: Relative difference between the brightest and darkest parts of an image. A contrast control adjusts the peak white level of a display device.
Controller: Generic term that typically refers to a combination preamp/surround processor or receiver. Can also refer to a handheld wireless remote.
Crossover: A component that divides an audio signal into two or more ranges by frequency, sending, for example, low frequencies to one output and high frequencies to another. An active crossover is powered and divides the line-level audio signal prior to amplification. A passive crossover uses no external power supply and may be used either at line level or, more commonly, at speaker level to divide the signal after amplification and send the low frequencies to the woofer and the high frequencies to the tweeter.
Crossover Frequency: The frequency at which an audio signal is divided. 80 Hz is a typical subwoofer crossover point and is the recommended crossover point in theatrical and home THX systems. Frequencies below 80 Hz are sent to the subwoofer; signals above 80 Hz are sent to the main speakers.
Crossover Slope: The rate of attenuation expressed in decibels of change for every octave away from the crossover frequency.
CRT: See Cathode Ray Tube.
Cut: To reduce, lower; opposite of boost.