Audio Terminology And Definitions Dictionary

 

C  Symbol for capacitance and centigrade.

 

Cantilever  Arm on which is fitted the stylus of a pickup cartridge.

 

Capacitance  A measure of reactance (units: Farad, pF, uF etc).

 

Capacitor  Solid state device used in electronic circuits and loudspeaker crossover networks to introduce a required level of capacitance.

 

Cartridge  The small component fitted to the front end of a tonearm. Contains the stylus and electro- magnetic system required to track a vinyl record (LP or single) and feed output to an amplifier phono stage. There are two main types of hi-fi pickup cartridge - the 'moving magnet' and 'moving coil'. 

 

Cassette  Audio cassette or analogue cassette. Contains blank or pre-recorded tape on spools constrained within a case or cassette.

 

Cassette Deck The machine required to play and/or record onto an audio cassette.

 

CAV (Constant Angular Velocity) Laserdisc operating format in which the disc rotates at a constant speed during play. CAV permits more special effects (still-frame, slowmotion, and fastmotion, for example), but this format is somewhat wasteful of disc space. CAV discs are limited to thirty minutes of material on each side of a 12-inch laser disc. (See also: CLV.)

 

CBR (Constant Bitrate)    CBR encoding uses roughly the same amount of memory to encode both the simple and complex passages of a source file. Thus, the user is likely to experience audible or visible loss of quality during complex parts, especially with lower bitrate files. Most newer audio and video codecs employ a technology known as variable-bitrate (VBR) encoding, which allows resulting files to look and sound better while still retaining a compressed, convenient file size. In contrast to CBR, VBR encoding assigns more bits to the complexly detailed portions of the original source and fewer bits to the simpler portions.

 

CD (Compact Disc)  Different formats of CDs are used for various applications. For example, CD-DA (Compact Disc–Digital Audio) is used for music, and CD-R and CD-RW (recordable formats) are used for data.

 

CDi  Compact Disc Interactive. An offshoot technology from CD, developed by Philips as an educational and entertainment format providing interactive still and moving  pictures and audio sound.

 

CD-ROM (Compact Disc—Read Only Memory) Refers to both the media and the format for storing digital data (computer files or music information) on compact discs. Because of its high information density, an ordinary CD-ROM can be used to store up to 680MB of digital information.

 

Center Channel In a multi-channel home theater system, the center channel is primarily responsible for conveying on-screen dialog. Depending on how a movie or TV broadcast was originally recorded and the method used to bring the sound from studio to home, the center channel usually carries well over 60 to 75 percent of the sound we hear.

 

Center Channel Speaker     The speaker in a multi-channel home theater system that is placed midway between the main left and right speakers at the front of the main listening/viewing area. The center channel speaker is most often placed just above or below a display, or it can be concealed directly behind an acoustically transparent screen if used with a two-piece projection system. Center channel speakers reproduce, as you might expect, center channel information only.

 

Circle Surround     A surround sound encoding/decoding format developed and marketed by SRS Labs. It processes audio data differently than Dolby or DTS codecs with the intention of providing a more immersive sonic experience.

 

Clipping  A signal-altering condition that occurs when an amplifier cannot accurately amplify the shape of the input signal because of current and voltage limitations. When viewed on an oscilloscope, a clipped signal shows substantial flattening of both positive and negative peaks, almost as if these peaks had been "clipped off" by a pair of shears. A clipped signal contains large amounts of harmonic distortion and can be more damaging to loudspeakers than an undistorted signal of equal or even greater power.

 

CLV (Constant Linear Velocity)  Laserdisc operating format in which the rotational speed of the disc varies as the laser pickup travels from the inner edge to the outer edge of the disc. This maintains a constant velocity of data past the laser pickup and allows more efficient use of disc space, resulting in sixty minutes of material on each side of a 12-inch laser disc. The downside of CLV compared to CAV is that CLV does not allow the special effects capabilities of the CAV format. CLV is also the operating format for compact discs. (See also: CAV.)

 

Codec  A method for compressing and decompressing digital files (co-dec). Each codec uses a slightly different set of algorithms to accomplish this goal.

 

Coloration  A relatively indefinite term that describes unwanted alteration (i.e., distortion) of the original signal. Speakers are more likely to "color" the sound than are other components.

 

Compact Disc  The first commercially available digital audio playback format. Software is a 12cm diameter single sided silver disc containing digitally encoded signal to a 44.1kHz, 16-bit standard. Optical playback is by means of laser beam. Developed jointly by Philips and Sony CD has spawned a number of offshoot audio/video technologies such as CDi and CD-ROM.

 

Compliance  A measure of the springiness in a component. A cantilever suspension, moving coil  speaker drive unit suspension, CD player isolation feet etc. 

 

Component Video Connection   A type of video connection in which the distinct color and black-and-white elements of the signal are transferred via separate cables from a source to a video display. Three RCA cables with red, green, and blue connections are used. There are two types of component video connections in use for consumers:

·   Y,Pb,Pr: progressive scan–capable component video input/output connection
·   Y,Cb,Cr: interlaced scan–only component video input/output connection

(See also: Y, Pb, Pr and Y, Cb, Cr.)

 

Composite Video Connection     A connection in which both the color (chrominance) and black-and-white (luminance) portions of a video signal are transferred via a single RCA video cable, usually one with yellow connectors. A composite video connection is inferior in quality to a component video connection.

 

Compression  A way of reducing the storage requirements, transmission time, or both of digital data. Compression can be either "lossy" (i.e., some data is irretrievably thrown out during the process) or "lossless" (the recovered data is a bit-for-bit replica of the original).

 

Container Format A file structure that holds different kinds of data within a single file. Container formats (e.g., RealAudio and TIFF) are gaining popularity because of their multimedia applications and their cross-platform compatibility. For example, a single container file can hold chapter information, hyperlinks, and subtitles, as well as different kinds of codecs that enable various types of players to read the file.

 

Continuous Calibration Designed by Philips, continuous calibration is a low-bit D/A converter with a constant weighing circuit that keeps the D/A process linear and improves resolution.

 

Contrast Ratio  Contrast ratio is the difference between the brightest whites and the blackest blacks that a video display device can deliver. There are several methods of defining contrast ratios, and specific numbers can rarely be compared without referring to the measurement method used. Look for "native" or ANSI (American National Standards Institute) specifications rather than "dynamic" measurements.

 

Crossover   A circuit (technically, a superposition of at least two filters) that divides an audio signal into parts above and below what is often known as the "corner frequency" or "crossover frequency." The rate at which a crossover divides the spectrum is called the "slope." 

If you see a crossover described as "400 Hz @ 18 dB/octave," the crossover's corner frequency is 400 Hz. The low-pass filter reduces high-frequency output by 18 dB one octave below that point, and the high-pass filter reduces low-frequency output by 18 dB one octave above that mark.

Crossovers usually are used to separate a wide-range audio signal into more narrow-range components so that each component may be safely directed to specialized loudspeaker drivers (woofers, tweeters, etc.) for optimum reproduction. Crossovers are usually categorized by their complexity (two-way, three-way, four-way, etc.).

Functionally, crossovers are categorized as "passive" or "active." Passive crossovers (sometimes called "high-level" crossovers) are usually found inside loudspeaker enclosures. They divide the audio signal after it has been amplified and send the different portions to the appropriate loudspeaker system drivers. Active crossovers (sometimes called "electronic" or "line-level" crossovers) divide the signal prior to amplification and thus require separate amplifiers for each frequency segment. Active crossovers are more precise, but usually they are more costly to implement correctly. Powered subwoofers may use either active or passive crossovers.

 

Cycles Per Second More commonly known as Hertz (abbr: Hz) after the German who discovered the nature of audio frequencies. It is the speed of movement of a sine wave or cycle that determines its frequency, and in turn the musical pitch of a note..