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.
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
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.
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.