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.

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DAC - Digital to Analog Converter. Electronic circuit built into various devices to convert digital data to analog for amplification or display by other devices.

dB - Decibel. A measurement of the loudness of a sound; technically, the sound pressure level. The decibel scale is logarithmic and so a 10 dB represents a doubling of the sound level; so 60dB is twice as loud as 50dB.

DDD - Digital Digital Digital. A designation that indicates the recorded material was first recorded with digital equipment, then remixed on digital equipment and finally placed onto a digital recording medium..

Deinterlacer - A device, or circuit in a device, which converts interlaced video to progressive scan video. Interlaced pictures are painted in two passes. Every other line is painted in the first pass and the alternate lines are painted on the second pass. A deinterlacer, aka line doubler, creates a complete picture, filling in all of the lines, for each scan. More lines results in a better picture.

Digital Cable Ready (DCR) - A TV or product that is equipped with a CableCard slot and thus enabled to receive encrypted cable signals without the need for a set-top box (STB).

Direct View - A television based upon direct view CRT technology. While rear projection CRT TVs use CRTs, they are not viewed directly but rather are reflected.

DLP - Digital light processing. A rear projection television based upon technology that uses a chip with hundreds of thousands of microscopic moving mirrors. Each mirror corresponds to a single pixel on the screen. Light is reflected through an RGB color wheel to create the required colors. More expensive models use three separate mirror devices, one for each color, instead of using a color wheel. For more information, see our article on TV technologies.

Dolby Surround - Dolby laboratories developed surround sound which distributes audio signals to speakers placed around the room to create an effect of directional and ambient sound. There are several Dolby products the most well known of which are ProLogic and Dolby Digital. For more information, see our article on surround sound.

Downconvert - The conversion of a higher resolution television signal to a lower one. For example, some networks broadcast HDTV at 1080i, while many plasma screens display 752 lines. Therefore, the signal must be downconverted to be displayed on the screen. Because of the many different resolutions used in home theater, downconversion and upconversion processes are frequently required. The quality of the process varies by manufacturer and viewer preference.

DSP - Digital Signal Processing. An electronic circuit for the enhancement of signals after conversion from analog.

DSS - Digital Satellite System. A subscriber satellite broadcast service similar to cable television.  Network and premium television signals are beamed from geosynchronous satellites to personal receiver dish antennas.

DTS - Digital Theater Systems. A surround sound technology directly competing with the Dolby surround standards. Products include DTS-ES and DTS:NEO6. For more information, see our article on surround sound.

DTV - Digital Television. The generic overall term for the digital video broadcast (ATSC) adopted to replace the old analog standard (NTSC). It consists of 18 different formats, all of which must be supported by new digital ready televisions. For more information, see our article on HD Television.

D-VCR or D-VHS - Digital VCR. Similar to standard VHS VCRs except that they have the capability to record and playback HDTV.

DVD - Digital Versatile (or Video) Disc. A 5-inch diameter optical disc used for the recording of movies, music, software and data. The term is also sometimes used to refer to the DVD player.

DVI - Digital Visual Interface. A digital video signal connectivity standard that uses an uncompressed digital signal. DVI does not carry an audio signal, while the similar HDMI standard does. DVI signals are used in both home theater and computing. The DVI-I connector carries digital or analog while the DVI-D carries digital only. The two are compatible although an adapter may be needed to connect one to the other.

DVR - Digital Video Recorder. aka PVR or Personal Video Recorder. Similar to a VCR although with much greater capabilities. A DVR records to an internal hard disk drive. It can record and play back a different recording simultaneously. With it you can pause live television and in some cases record more than one show simultaneously. It allows for easy set-up to record a program one time or on an ongoing basis. While once a subscription product available from a small number of companies like Tivo or Replay, many cable companies and satellite systems are now offering the service.