DAC: An acronym for Digital Analog Converter. One of two chips in an A/V receiver that decodes surround-sound formats. The DAC converts digitally encoded music signals into analog signals that a receiver’s amplifier and the surround speakers can understand.

deep color: A system supported by high-end HDTVs that provides higher (than typical) levels of color depth, capable of supporting millions of colors.

digital audio file: Just like any other file on your computer, except they contain digitally encoded music files that you can play back on your computer, on a portable device, or in your home theater.

digital cable-ready: A feature of most HDTVs that enables you to connect a coaxial cable from the wall directly to the TV, skipping a set-top box (for nonscrambled channels).

digital rights management; DRM: A music or video system that places restrictions on copying or recording digital assets. Protects the copyright interests of music, movie, and other content owners.

Digital Theater Systems: DTS is a company that has invented and developed several surround-sound encoding schemes, including the lossless surround-sound format known as DTS-HD.

dipole: A pole position of speakers in which the drivers are on two faces, opposite each other. Dipole speakers are designed for side or rear surround sound in a home theater. They fire their cones at different times, out of phase.

direct-view display: A type of display in which the image is created directly on the screen you are watching. Includes old-fashioned tube TVs, plasma displays, and LCD TVs.

discrete: A sound signal contained in each of the available audio channels that is distinct and independent from each of the others.

display: The device in a home theater that shows the picture. Includes direct-view displays (tube, plasma, or LCD TVs) and the separate screen in a front-projection system.

distortion: A specification that indicates the level of noise created by an amplifier's power output (the lower, the better).

DLP: An acronym for Digital Light Processor. DLP is a method of projecting video in projector systems, developed by Texas Instruments. Uses a special video chip with millions of microscopic mirrors that are moved by computer command to create images.

Dolby Digital: An all-digital surround-sound format developed by Dolby Laboratories (in 1997) that handles audio compression, available only for digital content.

Dolby Digital Plus: An all-digital surround-sound format developed by Dolby Laboratories that is an improvement on the older Dolby Digital and Dolby Digital Surround EX systems. Enhancements include an increased bit rate, improved sound encoding, more discrete channels of sound, and backward compatibility.

Dolby Digital Surround EX: An all-digital surround-sound format developed by Dolby Laboratories that improves on the older Dolby Digital system. Includes an additional rear (center) surround speaker with a matrixed (intermixed) signal from the left and right surround channels.

Dolby Pro Logic: An older surround-sound format developed by Dolby Laboratories that includes four channels and five speakers of matrixed (intermixed) multichannel surround sound. An improvement on the Dolby Surround Sound format. Newer enhanced versions include Dolby Pro Logic II and Dolby Pro Logic II.x.

Dolby Surround Sound: The original surround-sound format developed by Dolby Laboratories that encodes four analog audio channels into two channels.

Dolby TrueHD: An all-digital lossless surround-sound format developed by Dolby Laboratories that supports up to 13.1 channels of surround-sound.

drivers: 1. (noun) The round elements inside a speaker enclosure that move back and forth and create changes in the air pressure (sound waves). 2. (noun) Software files that integrate hardware devices with a PC's operating system.

DSP: An acronym for Digital Signal Processor. One of two chips in an A/V receiver that decodes surround-sound formats. The DSP sends the music signals to the correct channels and also can provide sound field enhancements (echo effects).

DSS: An acronym for Digital Satellite Service. DSS is a TV source that receives a signal from a satellite dish. The two main DSS services in the U.S. are DirecTV and DISH Network.

DSS receiver: A device that decodes television signals feeding in from a satellite dish so that your TV can display the programming.

DTS-HD: A lossless surround-sound format on Blu-ray discs and players that can provide up to 7.1 channels of surround sound. There are two variants: DTS-HD High-Resolution Audio (similar to Dolby Digital Plus) and DTS-HD Master Audio (similar to Dolby TrueHD).

dual-layer disc: A DVD or Blu-ray disc in which you can store media on both sides of the disc, doubling the capacity of a single-layer disc.

DVD: 1. (noun) A high-capacity optical disc resembling a CD, used primarily for storing video (such as movies) and data. 2. (noun) Other forms of the term DVD indicate a standard for the way data is stored on the disc, such as DVD+RW for a rewriteable disc format.

DVD decoder: A device that performs hardware-based decoding of the MPEG video on DVDs. This frees up your computer’s main processor for other tasks (recommended if you have a slower PC that you want to use in your home theater).

DVD-A: DVD-Audio. A newer digital audio format on DVD that offers higher-quality sound and greater capacity than a CD. The DVD-Audio format is not intended for video.

DVI: An acronym for Digital Visual Interface. DVI is a digital video technology that was developed as a means to connect computers to digital LCD screens and projectors.

DVR: Digital video recorder. A home theater device that records video onto a standard computer hard drive. DVRs (also called PVRs) connect to a program service, usually via a telephone line. TiVo is a major manufacturer of DVRs.

dynamic range: When pertaining to audio CDs, the difference between the softest and loudest musical passages on a compact disc.