Glossary of Home Theater Terminology
Glossary of Audio, Video and Home Theater Terms
There is a very large vocabulary of technical and descriptive terms that go with home theater. We've included the terms that you are most likely to encounter. If you are very technically involved you may find some of the more technical terms omitted from our list.
Click on a letter to jump to that section of our glossary.
C - The color, or chrominance signal representing all colors. Its amplitude represents the color intensity (saturation) and its phase represents the color itself (hue). When combined with the luminance (Y) signal it contains all the necessary data to create an image on the screen. S-Video carries the Y and C signals on separate wires to minimize loss of picture quality.
CableCard - Roughly the size of a double thick credit card, this device is designed to take the place of your cable TV set-top-box. The TV must be equipped with a CableCard slot to use the card. At this time, CableCards (which are provided to you through your cable company) do not support all the services your provider may offer such as "on demand" movies or interactive menus.
Calibration - As it relates to video, calibration refers to adjusting the video display to adhere to a standard. As it relates to audio, calibration refers to adjusting the sound level of each channel to match the level of all other channels.
CATV - Cable Television.
Cb, Cr - Component video is comprised by three signals. One signal is luminance which is signified by "Y". The second signal is blue, represented by "B" and finally red, represented by "R". "P" describes an analog signal while "C" indicates a digital signal. Depending upon equipment and cables, the signals may alternatively be labeled as "B - Y " or "Pb" and "R - Y" or "Pr" respectively.
C-Band - A range of the RF spectrum used by networks and cable companies to distribute programming via geo-stationary satellites. Consumers can also receive these signals using large (8 feet) satellite dish antennas.
CD - Compact Disk. A storage medium for audio, video or data. It can hold roughly 700 megabytes of data.
CD-R - Compact Disk - Recordable. A storage medium for audio, video or data. It can hold roughly 700 megabytes of data. Identical in appearance to a CD with the added feature that it can be recorded upon one time with the use of compatible recording equipment. The term is also used to refer to the recording equipment. Some but not all equipment that can play a CD can read and play a CD-R.
CD-RW - Compact Disk - Rewritable. A storage medium for audio, video or data. It can hold roughly 700 megabytes of data. Identical in appearance to a CD with the added feature that it can be recorded upon repeatedly with the use of compatible recording equipment. The term is also used to refer to the recording equipment. Some but not all equipment that can play a CD can read and play a CD-RW.
CEDIA - Custom Electronic Design and Installation Association.
CEMA - Consumer Electronics Manufacturers Association.
Center Channel - In a surround sound system, one channel is designated for primarily carrying dialogue and sounds that would occur directly in front of the viewer. A surround sound speaker is typically placed immediately above or below the screen.
Channel - In a surround sound system, the soundtrack of a film is divided to different speakers to deliver the sounds to approximate their source location in the film.
Channel Block - A feature on some televisions that allows a channel to be blocked from regular viewing until the channel is specifically unlocked.
Channel Separation - In audio, a measurement of the amount of leakage between channels, specified in dB.
Chapter - The content on a DVD is usually indexed into chapters for quick selection and access enabling the viewer to skip to a particular chapter on the disk.
Chrominance - The color portion of a video signal. The chrominance channel carries the color signal that when combined with the luminance channel, creates the complete picture. S-video is comprised by the chrominance "C" and the luminance "Y" signals and is represented as "Y C".
CL2 - The United States National Electric Code (NEC) requires wiring used in walls, ceilings or under the home to be burn resistant. CL2 refers to "Class 2" wiring, which at the time of writing (2012) is acceptable for home audio use. Specifically this relates primarily to speaker wire. If you run speaker wire inside walls, under floors, or through your attic, it must be at least CL2 rated. There are several other ratings that are also acceptable but CL2 is most commonly used.
Coax or Coaxial Cable - A round cable commonly used for bringing signals from an antenna or cable provider into a home. This 75-ohm cable is used for longer runs because of its low relative signal loss. However, the use of coax should be limited to those purposes because of it is inferior to other signal carrying wires. RG6, RG11 and RG59 are common varieties of coaxial cable.
Codec - enCOder/DECoder. A process for encoding a signal for transmission and then decoding it for playback. Dolby Surround and ProLogic are an example of a Codec.
Color Temperature - Light comes in various colors and it is measured in temperature, specifically, degrees Kelvin. A TV starts with a white base and adds color to the white base to make the picture. How the base "white" is set will affect how all other colors appear. The higher temperature, the bluer it will appear. 6500K is the standard temperature for white used for most TVs.
Comb filter - Built into many TVs, this device removes residual chrominance and luminance. Comb filtering enhances detail, outlines and color. However, they are not needed or used when then signal arrives by S-Video, component video, DVI or HDMI cable because they deliver a signal that requires no filtering.
Component Video - An analog video signal carried on three wires. A separate signal is carried for luminance, blue and red (green is derived). Component video may be referred to as "Y, B-Y, R-Y", "Y Pb Pr" or "Y Cb Cr", the terms are used interchangeably. A component video signal is carried on component video cables, which provides a very high quality signal; a step above S-video. This is the minimum quality connection to enjoy the benefits of an HDTV signal or DVD progressive scan. At present, no digital component video consumer products exists, regardless of labels all signals are analog.
Composite Video - a video signal in which the luminance and chrominance information are both carried in a single wire. While better than an RF signal, this cable should be used only if no better connection is available.
Contrast Ratio - The difference between the brightest whites and darkest blacks a TV can display. High contrast ratios are important for a TV to be able display subtle color variations and to overcome ambient light.
Convergence - The alignment of three electron beams in a CRT based television to converge on one point. When a one red, one green and one blue beam converge, they create white light. The failure of these beams to converge precisely will result in color haloing of images on screen.
CRT - Cathode Ray Tube. A large glass vacuum tube in which a beam of electrons is fired at the phosphor coated screen. The energy causes the phosphors to glow, giving off light. A single tube is used in regular TVs while some rear projection and a few video projectors use three CRTs, one for each color channel.