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Audio/Video Terminology & Definitions


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1080i: 1080-line interlaced scan; the vertical resolution of some high-definition (HD) broadcasts. See "interlaced scanning".

1080p: 1080 progressive. Newest High Definition TV (HDTV) resolution standard using progressive scanning at 1920x1080 pixel resolution without interlacing.

1440p: a non-standard proposed resolution that doubles the verticle resolution of the 720p high-definition standard. So far there hasn't been a single release of a display device from a consumer electronics manufacturer that is advertised as a 1440p display. Only CMO announced plans of a 1440p LCD television but its due date has passed (late 2007).

3:2 Pulldown Recognition: 3:2 Inverse Telecine Digital technology developed by Faroudja to accurately convert and display content originally on celluloid film which runs at 24 frames per second, compared to the 30 fps rate of television. Film is usually recorded at 24 frames per second. NTSC video (North America) is 30 frames (60 fields) per second. In order to get smooth motion, the film frames are broken into video fields in a 3-2-3 sequence. 3 fields for the first film frame, 2 fields for the second film frame, and so on. If a line doubler doesn't compensate for the extra field during playback on a progressive-scan display, the image will have noticeable motion artifacts. A line doubler with 3:2 pulldown recognition or 3:2 inverse telecine can see this sequence in the signal and correct for it by making sure the last field in the first frame isn't mixed with the first field of the second frame.

3-D Color Management System: An auto-adjusting tool that ensures accurate color displays.

3-D Digital Gamma Correction: DigiScanTM HDTV Circuitry technologies. Adds subtle nuance to dark scenes and gives images greater depth by increasing the number of gradation shades at low brightness levels.

3-D Digital Noise Reduction: DigiScanTM HDTV Circuitry technologies. It precisely removes noise elements in video source (S-video and Composite) by comparing with the former and the latter pictures. It minimizes the influence on original pictures and produces clear and sharp pictures. 3D digital noise reduction works exclusively to 3D Y/C separation.

3-D Y/C Separation: Function within DigiScan™ HDTV Circuitry. 3D Y/C separation (for NTSC/ composite video) separates composite signal to Y (brightness) signal and C (color) signal, and provides clear and sharp images without cross color (rainbow effect).

480i: 480-line interlaced scan; the vertical resolution of standard-definition broadcasts, and the original resolution technology. See "interlaced scanning".

480p: 480-line progressive scan; the vertical resolution of standard-definition and some enhanced-definition (ED) broadcasts. See "progressive scanning".

5.1-Channel Surround System: A speaker setup that places one speaker above or below a television, two on either side of the display, and two beside or just behind the listener (standard surround). A subwoofer is to the front left of the listener. A surround system creates a more immersive, realistic sound experience-the more speakers, the richer the sound.

7.1-Channel Surround System: A speaker setup that places one speaker above or below a television, two on either side of the display, two beside or just behind the listener (standard surround), and two behind the listener (surround back channels). A subwoofer is to the front left of the listener. A surround system creates a more immersive, realistic sound experience-the more speakers, the richer the sound.

720p: 720 progressive. High Definition television in the ATSC DTV standard using progressive format at a 1280x720 pixels; 720p offers progressive scanning and a constant vertical resolution of 720 lines to better support motion.



Absorption: Reduction of acoustical energy usually by converting it into heat via friction using soft, fibrous materials.

AC3: Audio Codec 3. This was the original and more technical name for Dolby Digital. Replaced by marketing mavens when they realized that Dolby's name was not in the title. Some RF modulated, 5.1-encoded laser discs were labeled as AC3. Later versions were labeled as Dolby Digital.

Academy Curve: An intentional roll-off in a theatrical system's playback response above ~2kHz (to -18dB at 8kHz) to minimize noise in mono optical tracks. Some (many) transfers to home video of mono movies have neglected to add the Academy filter during transfer, giving many old movies a screechy sound they were never intended to have. A few home processors have an Academy filter option, making them a must for old-movie buffs. Has been used since 1938.

Acoustic Suspension: A sealed speaker enclosure that uses the air trapped in the cabinet as a reinforcing spring to help control the motion of the woofer(s).

Active: Powered. An active cross-over is electrically powered and divides the line-level signal prior to amplification. An active speaker includes an active crossover and built-in amplifier.

A/D: Analog to digital conversion.

ADC (Apple Display Connector): a proprietary modification of the DVI connector that combines analog and digital video signals, USB, and power all into one cable. Apple used ADC for its LCD-based Apple Cinema Displays and their final CRT displays, before deciding to use standard DVI connectors on later models.

Addressable Resolution: The inherent resolution of a display device (plasma screen, television, projector or monitor) which enables pixels to be individually addressed. The device, however, may not be capable of displaying this resolution.

Aliasing: An artifact produced by distorting or not using the high frequency components of an image, signal, data stream, etc. due to some limitation such as undersampling or inadequate detection bandwidth. The result is unwanted appearance of low frequency components (aliases) which must be filtered out and replaced with the missing high frequency components. The process of removal/replacement of frequencies is called "anti-aliasing".

Amplifier: A component that increases the gain or level of an audio signal.

AM: Amplitude modulated.

Analog IQ: An HP feature in microdisplay TVs that processes analog video to optimize visuals.

Analog: A form of data transmission using a continuously variable signal, in contrast to digital transmission, which uses discrete numerical steps.

Analog Tuner: A built-in television feature that decodes over-the-air (antenna-based) analog signals.

Analog TV: "Standard" television broadcasts analog TV. Analog signals vary continuously, representing fluctuations in color and brightness. NTSC is an analog system.

Anamorphic: Process that horizontally condenses (squeezes) a 16:9 image into a 4:3 space, preserving 25 percent more vertical resolution than letterboxing into the 4:3 space. For the signal to appear with correct geometry, the display must either horizontally expand or vertically squish the image. Used on about two or three promotional laser discs and many DVDs. Also called Enhanced for Widescreen or Enhanced for 16:9.

Anamorphically Squeezed: This process, which is used on few laserdiscs, a few DVDs and even fewer TV broadcasts, is used to achieve a widescreen image, where the image is considerably wider than standard NTSC fare, once it is 'unsqueezed'. The wider image is squeezed into the skinnier aspect ratio, which is usually the NTSC standard of 4:3/1.33:1. Unsqueezing can be done with a 'stretching circuits' in the TV. The end result (if left unsqueezed) is a picture with really skinny objects. Another option which has less detail, but is more widely used is letterboxing the picture.

ANSI Lumens: A unit that indicates lumen brightness of projectors. ANSI (American National Standards Institute) has established the standard for measurement of lumen brightness. For example, if one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same.

Anti-aliasing: In electronic communication, the term refers to the adding of additional images or parts of images so as to convince the eye that it sees something that cannot be represented digitally. The goal is usually to make curved or diagonal lines appear smooth, or to show straight horizontal or vertical lines in certain positions. Lines cannot be represented smoothly or in the proper position because the display device resolution is not sufficient to represent the image accurately. In practice, the eye is fooled into completing the edge between the background and foreground colors.

Artifacts: Unwanted visible effects in a picture created by disturbances in the transmission or image processing, for example "edge crawl" or "hanging dots" in analog pictures, or pixelation in digital images.

Anti Glare Protection Screen: Discerning viewers know that stray light can reduce the clarity of a picture, making some areas appear faded and others pale. An Anti Glare Screen minimizes the reflection of exterior dazzling light with its special screen coating, regardless of the location of the TV. This results in smooth pictures which are easy on the eyes. It also increases picture contrast and is scratch resistant.

Aspect Ratio: The ratio of image width to image height. Common motion-picture ratios are 1.85:1 and 2.35:1. Television screens are usually 1.33:1 (also known as 4:3), which is similar to the Academy standard for films in the '50s. HDTV is 1.78:1, or 16:9. When widescreen movies (films with aspect ratios wider than 1.33:1) are displayed on 1.33:1 televisions, the image must be letterboxed, anamorphically squeezed, or panned-and-scanned to fit the screen.

ATSC: Advanced Television Systems Committee. Government-directed committee that developed our digital television transmission system.

ATSC HD Antenna: An antenna that receives over-the-air high-definition television signals.

ATTC: The Advanced Television Technology Center is a private, non-profit corporation organized by members of the television broadcasting and consumer products industries to test and recommend solutions for delivery and reception of a new U.S. terrestrial transmission system for digital television (DTV) service, including high definition television (HDTV). The Technology Center operates a state-of-the-art laboratory facility that supports the needs of the U.S. television industry and private standards-setting bodies. Its primary activity is to facilitate implementation of digital television.

Attenuate: To turn down, reduce, decrease the level of; the opposite of boost.

Audio Distribution Amplifier: Also called an Audio Splitter. (See "Distribution Amplifier".)

Audio Converter: A device that changes the audio connection from one format to another. For instance, Digital Coaxial into Stereo Analog R/L Audio. (See "Converter".)

Audio Splitter: (See "Distribution Amplifier".)

A/V Surround Receiver: An audio/video component with a built-in radio tuner that will receive radio broadcasts on FM or AM, switch different audio and video input sources, and decode Dolby Digital or dts 5.1-channel soundtracks. A/V receivers also contain from five to seven internal amplifiers to amplify the audio signals for delivery to up to seven loudspeakers in a 7.1-channel home theater surround system. All A/V receivers also contain a separate Subwoofer output (the ".1" channel of 5.1 surround) to feed a powered subwoofer for deep bass effects.

Automatic Contrast Optimization: Analyzes the brightness of scenes frame by frame and automatically adjusts contrast to maximize intense detail.

A-Weighting: Measurement based roughly on the uneven frequency sensitivity of the human ear. The influences of low and high frequencies are reduced in comparison to midrange frequencies because people are most sensitive to midrange sounds.

AWG: The American Wire Gauge, is a wire-sizing standard, also known as the Brown and Sharpe wire gauge, used in North America to measure and regulate the thickness of conductive wires made from nonferrous metals. The higher a gauge number is, the thinner the wire will be. Here are a few common cable types we use every day, as well as the AWG sizes that correspond to them: Speaker Wire: 14 or 16 AWG,  Coaxial Cable: 18 or 20 AWG, CAT Cables: 24 AWG, and Telephone Cables: 22-28 AWG.



Balanced (XLR or Cannon) Connector: A secure 3-wire connector found on all professional and semi-pro sound equipment and on some upscale consumer A/V components, enabling very long cable runs without hum pickup or frequency response losses. Must be used with matching balanced connectors on an A/V processor, preamp, or A/V receiver.

Balanced Input: A connection with three conductors: two identical signal conductors that are 180 degrees out of phase with each other, and one ground. This type of connection is very resistant to line noise.

Balun: a device that joins a balanced line (one that has two conductors, with equal currents in opposite directions, such as a twisted pair cable) to an unbalanced line (one that has just one conductor and a ground, such as a coaxial cable). A balun is a type of transformer: it's used to convert an unbalanced signal to a balanced one or vice versa. Baluns isolate a transmission line and provide a balanced output. A typical use for a balun is in a television antenna. The term is derived by combining balanced and unbalanced. In a balun, one pair of terminals is balanced, that is, the currents are equal in magnitude and opposite in phase. The other pair of terminals is unbalanced; one side is connected to electrical ground and the other carries the signal. Balun transformers can be used between various parts of a wireless or cable communications system.   The following table denotes some common applications.

Banana Plugs: Use these instead of bare wire at the end of your speaker cables for convenient plug-in speaker (high-level) connections between your A/V receiver's speaker output terminals and your loudspeakers. No improvement in sound quality over bare wire. Virtually all 5-way binding posts on newer speakers and subwoofers accept either single or dual banana plugs. Many A/V receivers' speaker outputs also accept banana plugs if there is enough space. Note: Banana plugs won't work with older speakers' and receivers' plastic spring "push" connectors, which accept only bare wire. See "Pin Connectors".

Bandpass: A two-part filter that cuts both higher and lower frequencies around a center band. A bandpass enclosure cuts high frequencies by acoustic cancellation and low frequencies by natural physical limitations on bass response.

Bandwidth: In audio, the range of frequencies a device operates within. In video, the range of frequencies passed from the input to the output.

Bass: Low frequencies; those below approximately 200 Hz.

Bass Reflex: See "Port".

BBE Viva: An audio technology that creates realistic 3-D sound while preserving high-definition sound. Makes subtle sounds clearly audible.

Binding Posts: 5-way. A type of speaker cable input and receiver/amplifier output connector that accepts bare speaker wire when you unscrew the top and push the wire through the hole in the post, spade connectors, pins, and single or double banana plugs. Binding posts are only used for High-Level (also called Speaker-Level) connections for amplified audio signals from an A/V receiver's speaker outputs to the speakers.

Bipolar: 1) The condition of possessing two pole sets. In a conventional (non-FET) transistor, one pole set exists between the base and collector, and the other pole set exists between the base and emitter. 2) Speakers that consist of two driver arrays facing opposite directions and wired in electrical phase with one another to create a more diffuse soundstage.

Bipole Speakers: One type of surround speaker. In this instance two or more drivers are facing different directions, and their cones vibrate in phase. This causes an omni-directional sound.

Bi-Wiring: A method of connecting an amplifier or receiver to a speaker in which separate wires are run between the amp and the woofer and the amp and the tweeter.

Black Level: Light level of the darker portions of a video image. A black level control sets the light level of the darkest portion of the video signal to match that of the display's black level capability. Black is, of course, the absence of light. Many displays, however, have as much difficulty shutting off the light in the black portions of an image as they do creating light in the brighter portions. CRT-based displays usually have better black levels than DLP, plasma, and LCD, which rank, generally, in that order.

Black/White Enhancer: Produces higher contrast level, increases brightness and details in bright or dark images to provide customers high detail image quality.

Blu-ray: A new High Definition video disc standard developed by Sony and other partners that is not compatible with existing DVD players. A rival standard, HD-DVD, developed by Toshiba is currently engaged in a format "war" to decide which will become the High Definition video disc standard. Both are capable of delivering spectacular HD image quality on HD TV displays. Neither type of disc will play on a conventional DVD player, however, a Blu-ray or HD-DVD player will play conventional DVDs with the existing video quality.

Blu-ray disc (BD): A next-generation optical disc format developed specifically for recording and rewriting high-definition video, with enhanced storage capacity (25GB single-layer or 50GB double-layer). Thus named because it uses a blue-violet laser rather than the standard red laser used by CDs and DVDs. Jointly developed by the Blu-ray Disc Association and several consumer electronics and PC companies, including HP.

BNC Connector: A connector that has a bayonet-type shell with two small knobs on the female connector which lock into spiral slots in the male connector when it is twisted on. This connection is preferred by professionals because of its perfect 75ohm impedance and positive locking connection.

Boost: To increase, make louder or brighter; opposite of attenuate.

Bridging: Combining two channels of an amplifier to make one channel that's more powerful. One channel amplifies the positive portion of an audio signal and the other channel amplifies the negative portion, which are then combined at the output.

Brightness: For video, the overall light level of the entire image. A brightness control makes an image brighter; however, when it is combined with a contrast, or white level control, the brightness control is best used to define the black level of the image (see "Black Level"). For audio, something referred to as bright has too much treble or high-frequency sound.



CableCARD: A device built into new-generation televisions that allows digital cable reception without a set-top cable box.

Cascading Crossovers: Two crossovers used in series on the same signal in the same frequency range causing greater attenuation of the out-of-band signal. For example, using the crossover in a receiver's bass management setting and the one in a subwoofer simultaneously will create an exaggerated loss of signal.

CAT5: Category 5 cable, commonly known as Cat 5, is an unshielded twisted pair type cable designed for high signal integrity. The actual standard defines specific electrical properties of the wire, but it is most commonly known as being rated for its Ethernet capability of 100 Mbit/s. Its specific standard designation is EIA/TIA-568. Cat 5 cable typically has three twists per inch of each twisted pair of 24 gauge copper wires within the cable.

CAT5e: Similar to Cat 5 cable, but is enhanced to support speeds of up to 1000 megabits per second.

CAT6: an Ethernet cable standard defined by the Electronic Industries Association and Telecommunications Industry Association, commonly known as EIA/TIA. CAT6 is the 6th generation of twisted pair Ethernet cabling, containing 4 pairs of copper wire and, unlike CAT5, utilizes all four pairs. CAT6 supports Gigabit (1000 Mbps) Ethernet and supports communications at more than twice the speed of CAT5e, the other popular standard for Gigabit Ethernet cabling. As with all other types of twisted pair EIA/TIA cabling, CAT6 cable runs are limited to a maximum recommended run rate of 100m (328 feet). Twisted pair cable, like CAT6, comes in two main varieties: solid and stranded. Solid CAT6 cable supports longer runs and works best in fixed-wiring configurations, like office buildings. Stranded CAT6, on the other hand, is more pliable and better suited for shorter-distance, movable cabling, such as "patch" cables.

Cathode Ray Tube: (CRT) Analog display device that generates an image on a layer of phosphors that are driven by an electron gun.

CATV: Refers to cable television. Originated from "community antenna television."

CD: Compact Disc. Ubiquitous digital audio format. Uses 16-bit/44.1-kHz sampling rate PCM digital signal to encode roughly 74 or 80 minutes of two-channel, full-range audio onto a 5-inch disc.

CD-R: Recordable Compact Disc

CD-RW: Rewritable Compact Disc

CEA: The Consumer Electronics Association (CEA) membership unites more than 1700 companies within the U.S. consumer technology industry. Member-only resources include: exclusive information and unparalleled market research, networking opportunities with business advocates and leaders, up-to-date educational programs and technical training, exposure in extensive promotional programs, and representation from the voice of the industry, CEA, promoting and advancing member needs and interests.

CEDIA: The Custom Electronic Design & Installation Association (CEDIA), is a global trade association of companies that specialize in planning and installing electronic systems for the home. These systems include home networking, home automation and communication systems, media rooms, single or multi-room entertainment systems, and integrated whole-house subsystems providing control of lighting, security and HVAC systems. The association was founded in September 1989 and has a total membership of more than 3,000 member companies. The Cedia Expo Show is held annually in September.

Center Channel: In surround sound, the center speaker in a home theater setup. This speaker is ideally placed within one or two feet above or below the horizontal plane of the left and right speakers, and above or below the display device, unless placed behind a perforated screen. Placement is important, as voices and many effects in a multichannel mix come from this speaker. A center-channel speaker is placed above or below the TV screen, used to anchor the actor's dialogue and sounds occurring in the central part of the video image at the screen. The Center Channel is part of all Dolby Digital 5.1 and dts 5.1 surround formats.

Channel: In components and systems, a channel is a separate signal path. A four-channel amplifier has at least four separate inputs and four separate outputs.

Chroma: The color information contained in a video signal.

Chroma Delay: Slight horizontal shifting of color relative to the luminance details of the picture giving the appearance of a poorly done child's coloring book. It can result from less than perfect circuitry or cables where the color subsignals take a longer or shorter time to arrive at the display screen.

Chroma Upsampling Error: Also referred to as the “chroma bug”, this error occurs because most digital video has every two scan lines sharing the same coloration. The bug manifests itself as thin black horizontal strips occurring every other line, or alternating between two colors near edges of sharply contrasted color objects. A good place to spot this artifact is in the Toy Story main menu (the blue text).

Chrominance: (C) The color portion of a video signal.

Channel Leakage: This occurs with matrix-surround encoded material. What happens is that sound meant to be heard from one channel is also heard from another channel. Solved with new 5.1-channel Dolby Digital and 6-channel DTS sound systems by virtue of a discrete channel sound system.

CL2 / CL3 Rated: Professionally rated for in-wall installation and are certified by the National Electric Code. CL2 and CL3 are designations that describe how a cable performs in a fire. CL2 and CL3 rated cables are made with flame retardant and low-smoke materials to minimize risk if they are exposed to heat or flame. Before installing any cables behind a wall please consult your local building code.

Coaxial Cable: Standard 2-conductor shielded cable comprised of an outer woven metal shield (the ground connection) covered with plastic/nylon insulation and further insulated from the inner "hot" or positive wire. Used with RCA male plugs on each end for routing low-level analog audio signals from CD players, DVD players, cassette decks, set-top TV converter boxes, and satellite receivers to A/V receivers and amplifiers. The RCA plugs are often color-coded red for Right channel and white (or black) for Left. Also used for composite-video connection (color-coded yellow) and may be used for digital coaxial audio connection as well. Coaxial audio cable is also used between the A/V receiver's subwoofer output jack (color-coded purple) and the subwoofer line-in connection.

Codec: Mathematical algorithms used to compress large data signals into small spaces with minimal perceived loss of information. 

Coloration: Any change in the character of sound (such as an overemphasis on certain tones) that reduces naturalness.

Color Enhancer: Epson AccuCinemaTM Color Management provides a color enhancer that improves color detail with vivid colors in dark scenes.

Color LUT/3DLUT: An algorithmic function that provides customers the most life-like colors by auto adjusting colors to achieve the most desired coloring. It also provides more color adjustments to product more colors. This feature is included in the Epson AccuCinemaTM Color Management.

Color Mapping: An HP feature in microdisplay TVs that permits the display of true colors.

Color Temperature: A method of measuring the color of gray at different levels from black to white. Since color information overlays the black-and-white information in a TV signal, color temperature affects the entire range of color. Epson Livingstation provides five Color Temperature settings that express the level of brightness.

Color wheel: A multicolor (either three-color or the newer seven-color) spinning wheel through which light is passed to create and project an image in digital light processing. DLP is used in HP projectors and microdisplay TVs.

Comb Filter: An electronic filter that is used to separate luminance and color information from an input composite video signal. (Color and luminance must subsequently be recombined in a different way, namely isolate red, green, and blue content,ÿto produce the picture.) Comb filters are used in the medium grade to more expensive TV sets to perform the necessary task of separating the two. ÿNotch and bandpass filters, common on lower priced TV sets as an alternative, produce acceptable pictures but with more discoloration and limited horizontal resolution.

Component: In component (YPbPr or RGB) format, the video signal is separated into three components through three RCA-type jacks for even higher image quality. Component video is typically used with better DVD players and on some HDTV systems.

Component Video: Used for both Standard-quality video and High Definition video, it uses three coaxial cables with RCA male plugs color-coded red, green and blue (the three cables may be wrapped together for convenience) to carry analog Standard- or High-Definition video between a set-top satellite or cable-TV box to the A/V receiver and TV display or projector. Most new A/V receivers include component-video inputs and outputs that let you switch between different video sources. Typically refers to Y/Pb/Pr, which consists of three 75-ohm channels: one for luminance information, and two for color. Compared with an S-video signal, a Y/Pb/Pr signal carries more color detail. HDTV, DVD, and DBS are component video sources, though most DBS material is transcoded to component from composite signals. Note: Component video cables do NOT carry audio signals. You must connect separate audio cables (either analog or digital) to carry the sound portion of DVD and cable/satellite TV signals. Component-video connections deliver the best picture quality other than HDMI or DVI connectors.

Component Video connections (Y/PB/PR): Component video is the best method for connecting analog video signals. Y/PB/PR is ideal for DVD players and compatible satellite receivers. Uses separate connections for luminance (Y), blue color difference (PB) and red color difference (PR). RGB is a different type of connection, similar to VGA, and should not be confused with a Component cable with red, green, and blue colored connector ends.

Composite: In composite format, all video information is combined into one signal and broadcast through one RCA-type jack. Usually identified by a yellow colored RCA jack connector.

Composite Video: A single video connector that combines all the color (Chrominance) and brightness (Luminance) signals into one 75-ohm cable (hence "composite") using a single RCA male connector. Often color-coded yellow, it is the most common type of analog video connection between older VCRs and TVs (except for RF connectors). Use composite video only if your TV, VCR or DVD player lacks S-video or component-video connectors. Composite video will not carry High Def or progressive-scan video signals. Chrominance is carried in a 3.58-mHz sideband and filtered out by the TV's notch or comb filter. Poor filtering can result in dot crawl, hanging dots, or other image artifacts.

Compound Loading: See "Isobarik".

Compression: A method of electronically reducing the number of bits required to store or transmit data within a specified time or space. The video industry uses several types of compression methods but the method adopted for DTV and DVD is called MPEG2.

Contrast: Relative difference between the brightest and darkest parts of an image. A contrast control adjusts the peak white level of a display device.

Contrast Ratio: Difference between the brightest whites and the darkest blacks on a display. Generally, the larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate extraneous room light. However, there are limits to what the human eye will discern in terms of differences in contrast ratio.

Controller: Generic term that typically refers to a combination preamp/surround processor or receiver. Can also refer to a handheld wireless remote.

Converter: A converter box will allow you to convert one audio/video format into another audio/video format, without changing the resolution aspect ration, refresh rate, or other factors. For example, you can convert Composite Video or S-Video into an HDMI signal. This type of device is perfect for integrating older audio/video devices into the modern home theater. A converter that has scaling capabilities can change the input resolution and aspect ratio to match your display.  

Crossover: A component that divides an audio signal into two or more ranges by frequency, sending, for example, low frequencies to one output and high frequencies to another. An active crossover is powered and divides the line-level audio signal prior to amplification. A passive crossover uses no external power supply and may be used either at line level or, more commonly, at speaker level to divide the signal after amplification and send the low frequencies to the woofer and the high frequencies to the tweeter.

Crossover Frequency: The frequency at which an audio signal is divided. 80 Hz is a typical subwoofer crossover point and is the recommended crossover point in theatrical and home THX systems. Frequencies below 80 Hz are sent to the subwoofer; signals above 80 Hz are sent to the main speakers.

Crossover Slope: The rate of attenuation expressed in decibels of change for every octave away from the crossover frequency.

CRT (cathode-ray tube): The familiar heavy glass "picture tube" common to TV displays for over 50 years but now becoming obsolete, replaced by LCD and plasma flat-panel displays as well as DLP and LCD rear-projection and front-projection display. Capable of superb color accuracy and picture detail viewable over a wide angle. Large, heavy, and limited to a maximum of 36 inches diagonal screen size.

Cut: To reduce, lower; opposite of boost.



D/A: Digital to analog conversion.

Damping: Of or pertaining to the control of vibration by electrical or mechanical means.

Damping Material: Any material that absorbs sound waves and eliminates acoustic energy by converting it into a different form. Fibrous material, for example, turns acoustic energy into heat via friction.

D'Appolito: Vertically symmetrical driver array. Typically consists of a tweeter mounted between two woofers. Creates a more-vertically directional sound with evenly spaced lobes in the off-axis response when compared with asymmetrical driver arrays.

Dark Video Enhancement: Enhances details in dark scenes.

DBS (Digital Broadcast Satellite): Digital format for music and video that beams high-powered signals across North America from satellites orbiting above the equator to satellite dishes providing a wide range of programming in a high-quality digital format. Direct broadcast satellites are positioned above the equator in geostationary orbit, meaning that the satellite orbits at the same speed as the spin of the earth, so is always facing the same part of the globe. The satellites beam down a high-powered signal in a broad spectrum of radio frequencies. The small 18 inch satellite dishes receive the signal and transfer it to a decoder box in the home. The decoder box then decodes the digital data and supplies an analog video and audio signal to the video display and audio system. The digital video and audio feed from a direct broadcast satellite is encoded with MPEG-2 compression.

DDC (Display Data Channel): a VESA standard for communication between a monitor and a video adapter. Using DDC, a monitor can inform the video card about its properties, such as maximum resolution and color depth. The video card can then use this information to ensure that the user is presented with valid options for configuring the display.

DDWG: Digital Display Working Group. DDWG are the creators of the DVI specification.

Decibel (dB): A logarithmic measurement unit that describes a sound's relative loudness, though it can also be used to describe the relative difference between two power levels. A decibel is one tenth of a Bel. In sound, decibels generally measure a scale from 0 (the threshold of hearing) to 120-140 dB (the threshold of pain). A 3dB difference equates to a doubling of power. A 10dB difference is required to double the subjective volume. A 1dB difference over a broad frequency range is noticeable to most people, while a 0.2dB difference can affect the subjective impression of a sound.

De-interlacing: A feature that improves picture quality, producing a film-like richness. Sixty frames per second are shown as opposed to the standard 30 frames per second. (Also called "line doubling.")

Delay: The time difference between a sonic event and its perception at the listening position (sound traveling through space is delayed according to the distance it travels). People perceive spaciousness by the delay between the arrival of direct and reflected sound (larger spaces cause longer delays).

Diaphragm: The part of a dynamic loudspeaker attached to the voice coil that produces sound. It usually has the shape of a cone or dome.

Diffusion: In audio, the scattering of sound waves, reducing the sense of localization. In video, the scattering of light waves, reducing hot spotting, as in a diffusion screen.

Diffusor: Acoustical treatment device that preserves sound energy by reflecting it evenly in multiple directions, as opposed to a flat surface, which reflects a majority of the sound energy in one direction.

DigiScan Processing: Epson circuitry processing technology combines with PixelWorks DNXTM technology that uses video processing algorithms with 3:2 pull down to deliver more stable picture with motion pictures. DigiScan Processing uses digital mapping to convert a conventional TV image into its high definition equivalent. The system creates four times as much data for a more solid and more convincing picture.

Digital: Expressed or represented by a series of numbers. For example, a digital signal is expressed by the numerical value of the signal size at regular points in time. Sounds and pictures can be recorded, stored, and played back digitally with no distinguishable difference from the original if the time interval between samples is sufficiently small.

Digital 3LCD Optical Engine: Epson proprietary 10 lens element optical engine technology that delivers 1024 shades of gradations for clearer color details and smoother picture quality. The 10 bits LCD driver used by the optical engine provides a 720p true high HD quality that is six times the clarity and resolution of standard televisions.

Digital Audio Server: Essentially a hard drive, a digital audio server stores compressed audio files (like MP3 or WMA). Most include the processing to make the files, and all have the ability to play them back.

Digital Cable Ready: Term for an HDTV that conforms to the plug-and-play digital cable TV standard using CableCARDs. Users can plug the cable directly into an HDTV set, then enjoy HDTV and digital cable without having to use a separate set-top box.

Digital Coaxial Cable: Carries a multichannel audio signal between digital or electronic devices, separating sound into speaker-specific signals.

Digital Comb Filters 3D Y/C & 3D Digital Noise Reduction: Part of the DigiScanTM HDTV Circuitry technology. These are both types of digital comb filters and a digital comb filter provides and accurate means of separating the color from the black and white in the television signal, thereby improving overall color sensitivity and image clarity.

Digital Image: A video image converted into pixels. The numeric value of each pixel can be stored in a computer memory for subsequent processing and analysis.

Digital Theater Systems (DTS): An 8-channel sound format used in commercial movie theaters. Only 6 are used, and the sound is run off CD's. The supposed follow-up for home theater is DTS Coherent Acoustics.

Digital Tuner: A set-top or built-in television tuner that receives digital television signals. Also called "digital receiver."

Digital TV: In the U.S., this term is commonly used to refer to a TV set that can display HDTV broadcasts. Actually many HDTV sets use analog processing for HDTV, they have no HDTV tuner built in and the HDTV video signal fed from an external tuner has been fully decoded and converted to analog. On the other hand, the best display of analog broadcasts requires digital components, namely the comb filter and a de-interlacer and/or scaler.

Digital Verstaile Disc (DVD): Previously known as Digital Video Disc. It is a purely digital format use MPEG-1 and/or MPEG-2 compression. This may result in artifacts such as pixellation. The format is also has the ability to have multiple aspect ratios, several different versions of a movie with several different captions as well as Dolby Digital sound. Each disc consists of two layers so that when the end of one layer is reached, the laser beam focuses down to the next layer for a seamless layer change.

D-ILA: Direct Drive Image Light Amplifier. This Hughes/JVC technology uses a reflective LCD to create an image. A light source is then reflected off the reflective LCD and is directed through a lens to a screen.

Dipole: Speakers with drivers on opposite faces that are wired electrically out of phase, creating an area of cancellation to the sides. Recommended by THX for use as surround speakers, with null directed at the listener to create a more ambient and non-localizable effect.

Direct-Stream Digital: A format for encoding high-resolution audio signals. It uses a 1-bit encoder with a sampling rate of 2,822,400 samples per second (verses 44,100 for CD). Used to encode six high-resolution channels on SACD.

Direct View Television: Direct View is the formal name for a normal "tube" TV. They are based on large CRTs (cathode ray tubes) that project the image onto a the surface of a phosphor-lined glass screen which you view directly, hence the name. Some other devices, such as projectors may also use CRTs but they project the image onto a separate screen. Some of these sets may have their own internal line doubler or "upconverter" which is used to convert the incoming 15.75kHz (normal) signal to 31.5kHz (or higher).

Dispersion: The spread of sound over a wide area.

Distortion: Any undesired change in an audio signal between input and the output.

Distribution Amplifier: DAs, also called splitters, are used to divide a single video source or audio source and duplicate it into two or more identical copies of the original signal. DAs are available for both analog and digital audio and video signal types. Analog distribution amplifiers provide signal amplification and enhancement features such as fixed or variable peaking and gain. Digital distribution amplifiers provide appropriate signal buffering so that each of the outputs may be driven without affecting the data path integrity and bit error rate performance. In some cases, digital DAs will also reclock the signal at the output, ensuring that each of the output signals is at a data rate identical to the original signal.

DLP (digital light processing): A TV projection technology developed by Texas Instruments that uses a light source (projector bulb) bounced off the surface of a tiny chip, a digital micro-mirror device (DMD) whose surface is covered by many thousands of tiny, moveable mirrors. Maintenance-free and capable of bright, high-contrast images with good blacks and rich color.

DLP® technology: DLP® technology delivers the clearest, sharpest and most accurate images in a broad range of projection and display applications including business projectors, home entertainment projectors, large screen tabletop TVs, video walls and projection systems used in commercial entertainment. DLP Cinema® technology, which delivers large screen images that are superior in many respects to film, is helping to revolutionize the movie industry. At the core of every DLP® projection system is an optical semiconductor called the Digital Micromirror Device, or DMD, which functions as an extremely precise light switch. The DMD chip contains an array of more than a million hinged, microscopic mirrors. By switching these mirrors on and off up to several thousand times per second, a DLP® projection system can translate a digital video or graphic source into a projected image with maximum fidelity.

DMD: Digital Micromirror Device. Texas Instruments engine that powers DLP projectors. Uses an array with tens of thousands of microscopic mirrors that reflect a light source toward or away from the lens, creating an image. Each mirror represents a pixel. (See "DLP".)

DNR: Dynamic Noise Reduction. A signal-processing circuit that attempts to reduce the level of high-frequency noise. Unlike Dolby NR, DNR doesn't require preprocessing during recording.

Dolby B: A noise-reduction system that increases the level of high frequencies during recording and decreases them during playback.

Dolby C: An improvement on Dolby B that provides about twice as much noise reduction.

Dolby Digital 5.1 (DD 5.1): Developed by Dolby Labs, this digital surround format delivers up to 5.1 channels of sound. An encoding system that digitally compresses up to 5.1 discrete channels of audio (left front, center, right front, left surround, right surround, and LFE) into a single bitstream, which can be recorded onto a DVD, HDTV broadcast, or other form of digital media. When RF-modulated, it was included on some laser discs, which requires an RF-demodulator before the signal can be decoded. Five channels are full-range; the .1 channel is a band-limited LFE track. A Dolby Digital processor (found in most new receivers, preamps, and some DVD players) can decode this signal back into the 5.1 separate channels. Most films since 1992's Batman Returns have been recorded in a 5.1 digital format, though a number of films before that had 6-channel analog tracks that have been remastered into 5.1. Used throughout the world as the standard soundtrack format for DVDs and High Definition TV as well as for the vast majority of movie soundtracks. All six channels are carried on one digital coaxial cable or optical digital link (Toslink) from the DVD player to the AV receiver. Dolby Digital may also be used for as few as 2 channels, in which case it's DD 2.0. Not all movies are mixed in 5.1 channels.

Dolby EX: An enhancement to Dolby Digital that adds a surround back channel to 5.1 soundtracks. The sixth channel is matrixed from the left and right surround channels. Often referred to as 6.1. Sometimes referred to as 7.1 if the system uses two surround back speakers, even though both speakers reproduce the same signal. Software is backwards-compatible with 5.1 systems, but requires an EX or 6.1 processor to obtain additional benefit.

Dolby Pro Logic: An enhancement of the Dolby Surround decoding process. Pro Logic decoders derive left, center, right, and a mono surround channel from two-channel Dolby Surround–encoded material via matrix techniques.

Dolby Pro Logic II (DPLII; DPLIIx): An enhanced version of the older Dolby Pro Logic surround system, this format will simulate 5.1-channel playback from a 2-channel stereo source of any kind. The most recent DPLIIx version simulates up to 6.1 or 7.1 channels if one or two back surround speakers are connected. Adds improved decoding for two-channel, non-encoded soundtracks and music.

Dome: A type of speaker-driver shape; usually used for tweeters (convex). Concave domes are usually referred to as "inverted domes."

Dope: A tacky substance added to paper cones to damp spurious vibrations that can cause breakup and rough response. Also, see Editor.

Dot Crawl: An artifact of composite video signals that appears as a moving, zipper-like, vertical border between colors.

Dot Pitch: The (center to center) spacing between phosphor dots or stripes of the same color on a display screen. The smaller the better for picture sharpness, 0.28 mm is considered the minimum acceptable for a good computer display, while a typical 20" TV has an 0.81 mm dot pitch and large screen TV's have larger dot pitches. Many TV screens use vertical stripes rather than dots in which case the dot pitch applies only in the horizontal direction.

Downconvert: A term used to describe the format conversion from a higher resolution input signal number to a lower display number, such as 1080i input to 480i display.

Driver: A speaker without an enclosure; also refers to the active element of a speaker system that creates compressions and rarefactions in the air.

DSD: (See "Direct Stream Digital".)

DSP (Digital Signal Processing): Manipulating an audio signal digitally to create various possible effects at the output. Often refers to artificially generated surround effects derived from and applied to two-channel sources.

DTS (Digital Theater Sound): A rival digital soundtrack format to Dolby Digital that is an option on some DVDs. Also used in many movie theaters. A digital sound recording format, originally developed for theatrical film soundtracks, starting with Jurassic Park. Records 5.1 discrete channels of audio onto a handful of laser discs, CDs, and DVDs. Requires a player with DTS output connected to a DTS processor. It is not a required standard for DVD soundtracks but may be included at the option of the producer. Virtually all DVD players and A/V receivers will decode dts or Dolby Digital soundtracks.

DTS (Digital Theater Systems): A digital sound recording format, originally developed for theatrical film soundtracks, starting with Jurassic Park. Records 5.1 discrete channels of audio onto a handful of laser discs, CDs, and DVDs. Requires a player with DTS output connected to a DTS processor.

DTS ES: An enhanced version of the 5.1 DTS system. Like Dolby's Surround EX, a sixth channel is added. In some cases (DTS ES Discrete), the sixth channel is discrete. Software is backwards-compatible with 5.1 systems, but requires an ES or 6.1 processor to obtain additional benefit. Neo:6 is a subset of DTS ES that creates 6.1 from material with fewer original channels.

DTV (Digital Television): Umbrella term used for the ATSC system that will eventually replace our NTSC system in 2006. HDTV is a subset of the DTV system. While the FCC does not recognize specific scan rates in the adopted DTV system, typically accepted rates include 480i, 480p, 720p, and 1080i.

D-VHS (Digital VHS): Digital signals recorded onto magnetic tape. Greater capacity than typical VHS; can record compressed HDTV signals. See D-Theater

DVD: Officially known as the Digital Video Disc, though marketers unofficially refer to it as the Digital Versatile Disc. DVD uses a 5-inch disc with anywhere from 4.5 Gb (single layer, single-sided) to 17 Gb storage capacity (double-layer, double sided). It uses MPEG2 compression to encode 720:480p resolution, full-motion video and Dolby Digital to encode 5.1 channels of discrete audio. The disc can also contain PCM, DTS, and MPEG audio soundtracks and numerous other features. An audio-only version, DVD-A uses MLP to encode six channels of 24-bit/96-kHz audio.

DVD-A (DVD-Audio): An enhanced, high-resolution multichannel audio format that uses six or eight shielded RCA coaxial audio cables (sometimes bundled together) to carry analog surround-sound output from a DVD player capable of DVD-Audio playback. 24-bit/96-kHz audio encoded onto a DVD, usually using MLP lossless encoding. Many new A/V receivers have a six- or eight-channel Multichannel analog input set that accepts the multichannel analog audio output of DVD-Audio or SACD players. Don't confuse DVD-Audio with the usual Dolby Digital 5.1-channel or dts digital surround soundtrack of DVDs. DVD-Audio discs are playable only on Universal DVD players. Requires a DVD-A player and a controller with 6-channel inputs (or a proprietary digital link) for full compatibility.

DVD-R: A recordable DVD format similar to CD-R in that it is a write-once medium. Backed by Pioneer, Panasonic, Toshiba, and others.

DVD-RAM: A type of DVD media designed for storage and archiving of user information. A recordable DVD format similar to DVD-RW in that it is a re-writeable format. Unlike most other DVD formats, such as DVD-R, it is capable of being written to and erased over 100,000 times. Backed by Hitachi, Panasonic, Toshiba, and others.

DVD-RW: A recordable DVD format similar to CD-RW in that it is re-recordable medium. Backed by Sony, Philips, Yamaha, HP, and others.

D-VHS (Digital VHS): Digital signals recorded onto magnetic tape. Greater capacity than typical VHS; can record compressed HDTV signals.

DVI: Digital Visual Interface (DVI) is a type of cable and connection created in 1999 by the Digital Display Working Group (DDWG), which is a cooperative of technology companies including Silicon Image, Intel, Compaq, Fujitsu, HP, IBM and NEC. A large computer-like 18-pin connector that carries digital video signals, including High Definition signals, between a set-top HD cable or satellite box or DVD player and an HDTV set. DVI digital video signals are protected by HDCP (High-bandwidth Digital Content Protection) protocol, which prevents you from copying high-quality digital video. Connection standard developed by Intel for connecting computers to digital monitors such as flat panels and DLP projectors. A consumer electronics version, not necessarily compatible with the PC version, is used as a connection standard for HDTV tuners and displays. Transmits an uncompressed digital signal to the display. The latter version uses HDCP copy protection to prevent unauthorized copying. (See also "HDMI".) DVI is gradually being replaced by smaller HDMI connectors. DVI/HDMI adapters are available, and many HDTV displays and projectors have both types. The DVI 1.0 standard was originally created to enable digital-to-digital, high bandwidth data transfer between a computer and a flat screen monitor. However, because of DVIs ability to also process high-bandwidth HDTV video, interest was generated in the consumer electronics industry. DVI is the fastest way to transfer data or video. Using DVI with a digital display device, such as a projector or flat screen monitor, will create an entirely digital-to-digital connection, providing the consumer with the best quality image.
DVI-A: Analog Only

DVI-D: Digital Only

DVI-I: Digital and Analog

DVI Dual Link: Dual Link DVI supports 2x165 MHz (2048x1536 at 60 Hz, 1920x1080 at 85 Hz). A dual link implementation utilizes all 24 of the available pins.

DVI Single Link: Supports a maximum bandwidth of 165 MHz (1920x1080 at 60 Hz, 1280x1024 at 85Hz). A single link implementation utilizes 12 of the 24 available pins.

DVR (Digital Video Recorder): An outboard video recorder often supplied by cable TV or satellite TV systems which uses a large-capacity hard drive to record and store video programs, either in Standard Definition or High Definition along with the digital audio surround soundtracks. Often integrated with the cable-TV HD tuner or satellite tuner.

Dynamic Range: The difference between the lowest and the highest levels; in audio, it's often expressed in decibels. In video, it's listed as the contrast ratio.



EBU: The European Broadcasting Union (EBU) is the largest professional association of national broadcasters in the world. The Union has 72 active Members in 52 countries of Europe, North Africa and the Middle East, and 50 associate Members in 30 countries further afield. The EBU was founded in February 1950 by western European radio and television broadcasters. It merged with the OIRT - its counterpart in Eastern Europe - in 1993. The Union is in the forefront of research and development of new broadcast media, and has led or contributed to the development of many new radio and TV systems: radio data system (RDS), digital audio broadcasting (DAB), digital television (DVB), high- definition TV (HDTV). At its office in Brussels, the EBU represents the interests of public service broadcasters before the European institutions.

ED: Enhanced definition is a signal that is either 480p (NTSC) or 576p (PAL) that can be either 4:3 or 16:9. Fox has broadcast shows like 24 in EDTV with a 16:9 ratio.

EDID: Extended Display Identification Data is a VESA standard data format that contains basic information about a monitor and its capabilities, including vendor information, maximum image size, color characteristics, factory pre-set timings, frequency range limits, and character strings for the monitor name and serial number. The information is stored in the display and is used to communicate with the system through a Display Data Channel (DDC), which sites between the monitor and the PC graphics adapter. The system uses this information for configuration purposes, so the monitor and system can work together.

EDTV: Extended Definition Television. This CEA-adopted term (though originally mentioned in an April '99 HT article by Mike Wood and Mike McGann) is defined as those products that can display DTV images as 480p or higher.

Efficiency Rating: Level of sound output measured at a prescribed distance with a standard input power. Efficiency rating standard is 1 watt (2.83V at 8 ohms) at 1 meter over a specified frequency range and is measured in decibels.

Electrostatic: One of the oldest speaker design principles, electrostatic speakers are generally comprised of two fixed perforated panels with a constant high-voltage charge applied to them. In between these two panels is an extremely low-mass diaphragm to which the audio signal is applied, causing it to move. There are variations on this construction, but all electrostatic speakers are free from the magnets and voice coils used in conventional speakers.

EMI (electromagnetic interference): the disruption of operation of an electronic device when it is in the vicinity of an electromagnetic field (EM field) in the radio frequency (RF) spectrum that is caused by another electronic device.

Enclosure: The container of air that surrounds the rear of a speaker driver.

Enhanced for 16:9: (See "Anamorphic".)

Enhanced for Widescreen: (See "Anamorphic".)

Epson AccuCinemaTM Color Management: The proprietary Epson AccuCinema™ Color Management provides color accuracy and performance that meets Hollywood cinematic mastering standards for extraordinary picture quality. The Epson AccuCinemaTM Color Management contains Black/White Enhancer, Color Enhancer, Color LUT/3DLUT, and Edge Enhancer. Epson's HDTV delivers the ideal color temperature closest to 6500º Kelvin to produce bright and saturated colors. Epson believes that at such color temperature, the TV gets the most accurate RGB color combinations.

EQ: (See "Equalization" or "Equalizer".)

Equalization: Loosely, any type of relative frequency adjustment. Specifically, the process of changing the frequency balance of an electrical signal to alter the acoustical output.

Equalizer: A component designed to alter the frequency balance of an audio signal. Equalizers may be graphic, parametric, or a combination of both.

Ethernet (RJ45) Cable: commonly used in high-speed wired computer networks, such as local-area networks (LANs), broadband Internet, or connecting a cable modem or DSL modem to a wired router or wireless router. The end of an Ethernet cable, called an RJ45 or an 8P8C modular connector, looks a lot like a telephone line connector, but the Ethernet connector is larger and wider. An Ethernet cable has male RJ45 connectors on both ends, and the cables can be anywhere from a few feet to hundreds of feet long (or 1 to 70 meters). Ethernet cabling uses a twisted-pair wiring configuration, which helps reduce electromagnetic interference (EMI). Sometimes referred to as IEEE 802.3, but that designation refers to the standard by which Ethernet works. Sometimes, Ethernet is called 10BASE-T, 100BASE-TX, or 1000BASE-T, depending on the maximum speed of a particular cable.

EX: (See "Dolby EX".)

External Crossover: A standalone unit. (See "crossover".)



FCC: The Federal Communications Commission (FCC) is an independent United States government agency, directly responsible to Congress. The FCC was established by the Communications Act of 1934 and is charged with regulating interstate and international communications by radio, television, wire, satellite and cable. The FCC's jurisdiction covers the 50 states, the District of Columbia, and U.S. possessions.

Feedback: The transmission of current or voltage from the output of a device back to the input, where it interacts with the input signal to modify operation of the device. Feedback is positive when it's in phase with the input and negative when it's out of phase.

Fiber-Optic (Toslink): A thin plastic or glass-fiber cable that carries digital audio signals in an optical format via pulses of light. Uses a small, square plastic male connector on each end. Most modern A/V receivers and DVD players have both Toslink optical digital as well as coaxial digital audio connectors. No difference in sound quality between optical or coaxial digital connections, but optical links are not susceptible to hum or interference.

Field: Half of an interlaced video frame containing either all the odd or all the even numbered horizontal lines. The frame is the entire image consisting of two fields. An interlaced image such as the NTSC analog television standard draws all the odd lines of an image followed by all the even lines of an image (first drawing lines 1, 3, 5, 7, and so on then coming back to draw lines 2, 4, 6, 8, and so on). A field consists of all the odd or even lines that combine to create a complete image.

Firewire: A type of cabling technology for transferring data to and from digital devices at high speed. Some professional digital cameras and memory card readers connect to the computer over FireWire. FireWire card readers are typically faster than those that connect via USB. Also known as IEEE 1394.

FM: Frequency Modulated.

Fixed Pixel Display (FPD): An all encompassing term for technologies that have pixels rather than scan lines like a CRT. LCD, DLP, plasma and LCoS are popular technologies that are used in fixed pixel displays.

Flat Panel Display (FPD): A type of display that is much thinner compared with standard CRT based displays. Plasma and LCD screens are both types of FPDs.

Flat Screen: A type of picture tube, based on CRT technology, which has front glass which is flat rather than the typical curved surfaced. Not to be confused with flat panel displays.

Frame: One complete screen in a video image. A single frame is related to a single picture or a single photograph. By combining multiple frames in rapid succession, the illusion of motion is created. In the movies, 24 frames pass by every second. On television, there are 30 frames displayed each second.

Frames Per Second (FPS): A measure of the number of pictures (or frames) that are displayed per second to create a moving image. For TV, this is typically between 50 and 60 FPS.

Frequency: The number of cycles (vibrations) per second. In audio, audible frequencies commonly range from 20 to 20,000 cycles per second (Hz). In video, frequency is used to define the image resolution. Low-frequency video images depict large objects or images. Higher frequencies depict smaller objects (finer details).

Frequency Response: A measure of what frequencies can be reproduced and how accurately they are reproduced. A measurement of 20 to 20,000 Hz ± 3dB means those frequencies between 20 and 20,000 Hz can be reproduced no more than 3 dB above or below a reference frequency level.

Front Projection TV: a method of viewing that utilizes a video projector (usually mounted on the ceiling). The image is projected onto a separate unit, typically a retractable movie screen. The front projection method allows for projection onto screen sizes that exceed 300 inches. Front projection technologies include DLP® technology, CRT and LCD.

Front Projector: One type of viewing device. This is a separate unit that projects the image onto a separate screen allowing screen sizes of over 300".

Full-Range: A speaker designed to reproduce the full range (20 Hz to 20 kHz) of audio frequencies.


Gain: Increase in level or amplitude.

Gas Plasma Display: A type of monitor technology typically used to create large monitors that are only a few inches thick. The technology works by creating a matrix of red, green and blue pixels from plasma bubbles that are turned on or off by selectively powering them.

Gauge: (See "Wire Gauge".)

Graphic Equalizer: A type of equalizer with sliding controls that create a pattern representing a graph of the frequency-response changes. Raising sliders boosts the affected frequencies; lowering sliders cuts (attenuates) the affected frequencies.

Gray Scale: The ability for a video display to reproduce a neutral image color with a given input at various levels of intensity.



Hanging Dots: An artifact of composite video signals that appears as a stationary, zipper-like, horizontal border between colors.

Hard-matte: A filming technique where plates block out the top and bottom of the picture as it is being filmed in order to achieve a widescreen effect. The opposite is Soft-matte.

HDCP (High-Bandwidth Digital Content Protection): A standard, developed by Intel, that protects digital video and audio signals transmitted over DVI or HDMI connections between two HDCP-enabled devices. The nature of a digital signal makes it possible to create perfect copies of the original signal an unlimited number of times without degradation, something that is impossible with an analog signal. So, in order to protect copyright holders (movie studios, etc.) from having their programs copied and shared, the HDCP standard provides for the secure, encrypted transmission of digital signals.

* HDCP only functions across DVI or HDMI connections between two HDCP capable devices. The source device (such as a DVD player or HDTV tuner) encrypts the digital signal using the HDCP standard, then sends that signal over the DVI or HDMI connection to the receiving device (HDTV, etc.). The receiving device decodes the signal using HDCP and uses the signal as it is allowed.

* If one of your devices is HDCP compliant, but the other is not, then you cannot connect them using DVI or HDMI - you will get an error. However, you can still use the analog signal from the source device (eg: component video signal, S-video signal). HDCP does not apply to analog signals, only digital signals.

* The FCC approved HDCP as a "Digital Output Protection Technology" on August 4th, 2004. FCC regulations will require digital output protection technologies on all digital outputs from HDTV signal demodulators as of July 1st, 2005.

HD-DVD: A new High Definition videodisc standard developed by Toshiba and other partners that is not compatible with existing DVD players. A rival standard, Blu-ray (see above) developed by Sony is currently engaged in a format "war" to decide which will become the High Definition video disc standard. Both are capable of delivering spectacular HD image quality on HDTV displays. Neither type of disc will play on a conventional DVD player, however, a Blu-ray or HD-DVD player will play conventional DVDs with the existing video quality.

HDMI (High-Definition Multimedia Interface): Much smaller and more convenient than DVI, HDMI is a USB-like digital video connector that carries the same digital video signals as DVI (High Definition and Standard Definition) but with the added advantage of conveying a Dolby Digital surround sound bitstream. Copy protected with HDCP so you can't pirate high-quality digital video. No image superiority of one over the other. May or may not produce a slightly better picture quality than component video.
All versions of HDMI are backward and forward compatible. They will all work but non-1.3 products will not support extended bandwidth features of 1.3 devices like "Deep Color." An HDMI 1.3 Category 1 device can carry a signal with a pixel clock of 74.25 MHz. An HDMI 1.3 Category 2 device can carry a signal with a pixel clock greater than 74.25 MHz.

HDMI 1.0: This is the first version of HDMI and it was ratified in late 2002. It will decode most versions of audio contained in DVD and digital TV signals, including Dolby Digital and DTS.

HDMI 1.1: This version added DVD-Audio support, which means users with compatible disks and players can listen to 5.1 channel audio streams without the need for six separate audio RCA cables.

HDMI 1.2/1.2a: The main improvement on 1.1 is the addition of Super Audio CD (SACD) support, which means users no longer need to rely on iLink or analog cables to listen to SACDs. The standard also adds support for an as-yet unused Type A PC connector.

HDMI 1.3/1.3a/1.3b: Version 1.3 adds support for Dolby TrueHD and DTS-HD Master Audio which are used in Blu-ray and HD DVD players. As yet, the only device on the market that supports this standard is the PlayStation 3, but in the coming months most manufacturers plan to release compatible surround receivers. The standard also increases the bandwidth by a factor of two to 10Gbps. HDMI 1.3 products are compatible with HDTV's with a 120 Hz frame rate and Blu-ray, HD-DVD DVD players etc. with a 24 Hz frame rate. The latest HDMI 1.3 version offers: Higher Speed, Deep Color, Broader Color Space, New Mini Connector, Lip Sync, and new HD lossless audio formats.

HDR (Hard-Drive Recorder): Device that uses a computer hard drive to store compressed digital audio and video signals.

HD-SDI: High Definition Serial Digital Interface. This standard transmits audio and video over a single coaxial cable with a data rate of 1.485 Gbit/s. (See "SDI".)

HDTV (High-Definition TV): The new digital TV standard that features increased horizontal and vertical resolution, a choice of progressive or interlaced scanning, and a widescreen aspect ratio of 16:9 (the ratio of a screen image's width to its height) that conforms to the widescreen visual format of modern movies (older analog TVs have a squarish-looking 4:3 aspect ratio). The most common HD formats are either 720p (720 progressively scanned lines) or 1080i (1080 interlaced scanned lines) or some variation of these. DVDs, although digital, are Standard Definition (480i), which may be displayed as 480p. Some of the latest HD video displays are capable of 1080p clarity, a slight improvement over 720p or 1080i. The ATSC defines HDTV as a 16:9 image with twice the horizontal and vertical resolution of our existing system, accompanied by 5.1 channels of Dolby Digital audio. The CEA defines HDTV as an image with 720 progressive or 1080 interlaced active (top to bottom) scan lines. 1280:720p and 1920:1080i are typically accepted as high-definition scan rates.

* An analog TV signal in the U.S. has 525 scan lines for the image, and each image is refreshed every 30th of a      second (half of the scan lines are painted every 60th of a second in what is called an interlaced display). 480 of 525 scan lines are used to hold the picture. We can also call it 480i. The formats used in HDTV are as follows:

        •480i - 640 x 480 pixels interlaced
        •480p - 640 x 480 pixels progressive
        •720i/720p - 1280 x 720 pixels interlaced/progressive
        •1080i/1080p - 1920 x 1080 pixels interlaced/progressive

HDTV Antenna: An HDTV antenna is necessary to pick up the digital HDTV broadcast signal.

HDTV ATSC Tuner: An internal or external over-the-air tuner that receives high-definition television signals. Also called "ATSC HD tuner".

HDTV converter: An HDTV converter enables an analog television to display digitally transmitted programming by translating HDTV broadcast signals into analog signals. However, it should be noted that the picture and sound quality associated with HDTV can only be fully experienced through a high definition digital television set.

HDTV Decoder: An HDTV decoder enables your high definition television to receive channels broadcast in HDTV.

HDTV Receiver: Receives and displays free, over-the-air High Definition television. Capable of images with up to six times the detail of conventional television.

Hi-Fi Stereo: Feature found on VCRs that records or plays back stereo soundtracks with improved fidelity compared to using the linear stereo tracks.

High Gain Screen: Material that reflects more light than a reference material. Increases a projector's light output at the expense of uniformity.

High Pass: A filter that passes high frequencies, and attenuates low frequencies. Same as low cut.

Home Theater: Media and home electronics that deliver the movie theater experience at home. Generally involves at a minimum a DVD player, a television with a screen of 27 inches diagonal or more and an audio system that features Dolby Digital decoding and 5.1-channel surround sound speakers.

Home Theater in a Box: A complete home theater system in one box (or at least sold together as a package). Consists of five or more speakers, a subwoofer, and a receiver. May also include a DVD player.

Home Theater Receiver: The receiver is the heart of a home theater system; it enables a projector or television to intake and translate an incoming broadcast signal for display. Most receivers consist of an amplifier, decoder, AM/FM tuner, audio/video switcher and decoder.

Home Theater System: A home theater system is a combination of products configured in the home for the presentation of high-quality images and sound. Products typically found in home theater systems include a VCR, stereo television or HDTV, receiver and DVD.

Horizontal Resolution: A measure of the quality of a displayed image, relating to the number of vertical lines, or individual picture elements across the screen from left to right. The greater the number of vertical lines (or picture elements across the screen), the greater the resolution. Higher resolutions result in images which are better defined and complete. There are two primary HDTV standards, 1080i and 720p. With 1080i the resolution is set at 1920 pixels across (horizontal resolution) and 1080 pixels top to bottom (vertical resolution). The 720p standard provides for 1280 pixels across (horizontal resolution) and 720 top to bottom (vertical resolution).

Horizontal Scan Rate: The number of horizontal lines of information a video display can paint on to a screen in one second, given in hertz (Hz - cycles per second). The horizontal scan rate of analog NTSC video is 15,750 Hz, which, at a refresh rate of 60 screens per second gives 262.5 as the maximum number of lines that can be displayed (vertical resolution). In a similar way, a graphics projector with a horizontal scan rate of 63,000 Hz has a vertical resolution of 1,050, and a data grade projector (31,500 Hz horizontal scan rate) can furnish 525 horizontal lines.

Horn: A type of speaker that looks like a horn. These speakers have small drivers and very large mouths; the horn shape serves to transform the small radiating area of the driver into the much larger radiating area of the mouth of the horn.

HVAC (Heating, Ventilation & Air Conditioning): HVAC systems help to control the climate, and keep occupants comfortable by regulating the temperature and air flow. HVAC systems are also important to occupants' health, because a well regulated and maintained system will keep a home free from mold and other harmful organisms. In some environments, such as museums, HVAC systems are vitally important for the preservation of historic artifacts.

Hz: Hertz or cycles per second. Something that repeats a cycle once each second moves at a rate of 1 Hz.


IEEE 1394: The Institute of Electrical and Electronics Engineers specification 1394 (IEEE 1394 also called FireWire and iLink) is the transmission standard and connector found on many consumer electronics products, including camcorders, DTVs, set-top boxes, A/V receivers, and some DVD players. Most signals sent over IEEE 1394 are compressed, which means they can be recorded.

iLink: (See "IEEE 1394".)

Imaging: The ability to localize the individual sound sources in three-dimensional space.

Impedance: A measure of the impediment to the flow of alternating current, measured in ohms at a given frequency. Larger numbers mean higher resistance to current flow.

Integrated Amplifier: A combination preamp and amplifier.

Integrated HD: An HDTV that has a built-in high-definition receiver/tuner.

Interconnects: Any set of cables or connectors that link A/V equipment of all kinds, however, most commonly the term designates low-level RCA audio and video connectors rather than speaker cables. For example, RCA terminated cables connecting pre/pros and amps.

Interlace: Process of alternating scan lines to create a complete image. In CRT displays, every second field/frame is scanned between the first field/frame. The first field represents the odd lines; the second field represents the even lines. The fields are aligned and timed so that, with a still image, the human eye blurs the two fields together and sees them as one. Interlace scanning allows only half the lines to be transmitted and presented at any given moment. A 1080i HD signal transmits and displays only 540 lines per 60th of a second. 480i NTSC transmits and displays only 240 lines per 60th of a second. Motion in the image can make the fields noticeable. Interlaced images have motion artifacts when two fields don't match to create the complete frame, often most noticeable in film-based material.

Interlaced Scan: For television display, interlaced scanning refers to the process of transmitting and re-assembling a single picture frame from two passes of the image. First the odd lines (1,3,5,...) are transmitted together, and displayed on screen. Next, the even lines (2,4,6,...) for the same frame are transmitted and displayed. The entire frame is displayed in two passes, or scans, each taking 1/60th of a second. The human eye sees it as a single picture, however, because of the persistence of the CRT phosphor. Interlaced video was originally invented to reduce flicker given that video technology of the time could not draw video frames fast enough to keep the top of the picture from fading before the bottom of the picture was completed. (See also "Progressive Scan".)

Inverted Dome: A type of speaker-driver shape; usually used for tweeters (concave).

IR Remote Control: A type of wireless transmission using infrared light waves.

Isobarik: Also known as compound loading. By using two low frequency drivers (generally mounted face-to-face and wired electrically out-of-phase or mounted front-to-back in a shallow tube and wired electrically in phase) you can halve the volume of the cabinet without reducing the low frequency extension of the subwoofer.



Jack: Any female receptacle of an audio or video connector into which the plug, or male connector, is inserted. All connectors have male and female components, RCA plugs and jacks historically being the most common on consumer-grade audio/video equipment. Sometimes the terms jacks and plugs are used interchangeably.

Jitter: Small, rapid varitaions in waveform or image due most often to mechanical disturbances.

JPEG (Joint Photographic Experts Group): JPEG is a digital compression standard for still video images that allows the image to occupy less memory or disk space.



Kelvin (K): Unit of measurement used to describe the color of light produced by the TV screen.

Keystone: A form of video image distortion in which the top of the picture is wider than the bottom, or the left is taller than the right, or vice versa. The image is shaped like a trapezoid rather than a rectangle.

Keystone Correction: Feature found in front projectors designed to compensate for mounting situations when the centerline of the projector's lens is not perpendicular to the screen to allow greater mounting flexibility.

kHz: Kilohertz or one thousand Hz.

KVM: Short for keyboard, video and mouse.



Laser Disc: Now-defunct 12-inch disc format with excellent analog, FM-recorded video image, and either analog or CD-quality PCM-encoded audio. Later discs used one of the analog channels to record an RF-modulated Dolby Digital/AC3 soundtrack and/or used the PCM tracks to encoded a DTS soundtrack.

LCD (liquid-crystal display): Color LCD panels used in flat-panel TV and computer displays, and in rear- and front-TV projection sets. Maintenance-free and capable of high resolution. Less than perfect blacks because in most displays light shines through the LCD panels to illuminate the image. May produce grid-like "screen-door effect" if pixels are too coarse, but great improvements have been seen in recent sets. A display that consists of two polarizing transparent panels and a liquid crystal surface sandwiched in between. Voltage is applied to certain areas, causing the crystal to turn dark. A light source behind the panel transmits through transparent crystals and is mostly blocked by dark crystals.

LCD Projection (LCD or Liquid Crystal Display): is widely used in portable computers, digital watches and, more recently, in home entertainment products. An LCD display consists of a liquid crystal solution suspended between two glass plates. When an electric current is passed through the liquid crystal solution, it causes the crystals to align in a certain configuration. As a result, light can pass through certain crystals and not through others, thereby producing the projected image.

LCoS (Liquid Crystal on Silicon): could be considered a hybrid between LCD and DLP. LCD uses liquid crystals, one for each pixel, on glass panels. Light passes through these LCD panels on the way to the lens and is modulated by the liquid crystals as it passes. Thus it is a "transmissive" technology. On the other hand, DLP uses tiny mirrors, one for each pixel, to reflect light. DLP modulates the image by tilting the mirrors either into or away from the lens path. It is therefore a "reflective" technology. LCOS combines these two ideas. It is a reflective technology that uses liquid crystals instead of individual mirrors. In LCOS, liquid crystals are applied to a reflective mirror substrate. As the liquid crystals open and close, the light is either reflected from the mirror below, or blocked. This modulates the light and creates the image. LCOS-based projectors typically use three LCOS chips, one each to modulate light in the red, green, and blue channels. In this it is similar to an LCD projector which uses three LCD panels. Both LCOS and LCD projectors deliver the red, green, and blue components of the light to the screen simultaneously. There is no spinning color wheel used in these projectors as there is in single-chip DLP projectors.

Letterbox: Format used widely on laser disc and many DVDs to fit wide-aspect-ratio movies (1.85:1 and 2.35:1, for example) into a smaller frame, such as the 1.78:1 area of an anamorphic DVD or the 1.33:1 area of a laser disc or video tape. The image is shrunk to fit the screen, leaving blank space on the top and bottom. This process sacrifices some vertical detail that must be used to record the black bars.

LFE (Low Frequency Effects track): The .1 channel of a Dolby Digital, DTS, or SDDS soundtrack. The LFE is strictly low-frequency information (20 to 120 Hz, with 115 dB of dynamic range) that's added to the soundtrack for extra effect. This track does not inherently contain all the bass of the soundtrack.

Light-Valve Projector: One type of front projector. It combines the technologies of LCD projectors and CRT projectors. They offer exceptional detail and brightness.

Line Doubler: Digital video processor that enhances the picture quality of a video image by combining the two interlaced fields (all the odd lines followed by all the even lines) to produce a single progressive scan frame of the image. Each doubled field is then a complete frame that is projected 60 times per second. Line Doublers must also contain complex processing circuitry to compensate for the shortcomings of the incoming interlaced video, and the mismatches that could be created by combining the two fields. The result is an image with much greater detail and clarity than the original interlaced video source.

Line Doubling: A method of converting an interlaced picture into a progressively scanned picture. Special circuits combine the odd and even lines, then scan all 525 lines in 1/30th of a second. The result is improved detail enhancement from an interlaced source. High quality de-interlacers use techiques more complicated than just delivering each scan line twice.

Line Tripler/Quadrupler: Doubles, triples or quadruples the number of lines that make up a picture, therefore increasing detail, and ridding the picture of scan lines. Usually used with front projectors.

Line-Level (Low-Level): A level of electrical signals too low to make the average speaker move sufficiently. Amplifiers receive line-level signals and amplify them to speaker level.

Lip Sync. Error: A situation in motion pictures when the picture and sound do not match in time. The sound or the picture has been delayed, so, for example, the lips do not move in time to the speech.

LNB (Low-Noise Blocker): The receiving end of a satellite dish.

Low Pass: A filter that lets low frequencies go through but doesn't let high frequencies go through. Same as high cut.

Lumens: A standard for measuring light output, used for comparing projectors. However, the rating does not always match the perceived brightness. For example, if one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same.

Luminance: The black and white (Y) portion of a composite, Y/C, or Y/Pb/Pr video signal. Portion of a television transmission that controls brightness of the red, green, and blue proportions in a television picture. The standard luminance setting in a picture is 30 percent red, 60 percent green, and 10 percent blue. These numbers can be adjusted to produce varying colors, grays, whites, and blacks. The luminance channel carries the detail of a video signal. The color channel is laid on top of the luminance signal when creating a picture. Having a separate luminance channel ensures compatibility with black-and-white televisions.



Macrovision: Macrovision, Inc has developed an anti-taping process for video systems that output analog NTSC, PAL, RGB or YUV video. The video source may be from DVD, VCR, or set top box. Whether or not the anti-taping process is present on the video outputs is determined by the source. Macrovision works due to the differences in the way VCRs and televisions operate. The automatic gain control (AGC) circuits within a television are designed to respond slowly to change; those for a VCR are designed to respond quickly to change. The Macrovision technique attempts to take advantage of this by modifying the video signal so that a television will still display it properly, yet a VCR will not record a viewable picture. DVD players typically have Macrovision circuits built in to make copying of DVD movies “impossible”.

Main Channels: In a 5.1-channel surround system, the front left, center, and right channel speakers. In a stereo system, the front left and right speakers.

Matrixed Surround: Term used to describe the process to make Dolby Pro-Logic compatible material. It fits four channels of sound into a space meant for two channels. The center channel is decoded by using material common to both left/right channels, and the surround channel is decoded by extracting the sounds with inverse waveforms. This process results in channel leakage.

Matrix Switch: an electronic device capable of interconnecting many components in any desired combination. This includes devices like a VCR's input and the same VCR's output. This type of hook up makes it easy to use the same VCR for recording or play back. This switch allows any one of the inputs to be switched to any one or all of the outputs. Matrix switchers route multiple audio and video sources (input signals) to multiple audio and video destinations (output signals). Input sources include computers, cameras, DVD players, etc. Destinations include projectors, monitors, and computers etc. Matrix switchers route any input to any combination of outputs. Different matrix switchers can route different signals, such as composite video, S-Video, stereo audio and mono audio. Matrix switchers are used in corporate boardrooms, classrooms, restaurants, home theaters, and video conference rooms. This type of switching is ideal for whole-house application. For example, it may be necessary to view the DVD player in the bedroom while, at the same time, viewing the satellite receiver in the home theater.

Media Hub: An HP HDTV innovation that allows users to access, manage, and enjoy digital photos, music, TV, and video in one set-top device that combines the capabilities of HDTV, digital cable, and a dual-tuner digital video recorder. It includes an electronic program guide, a music information service, and an automatic update service that upgrades the device as new services become available.

Megachanger: CD or DVD player with massive disc storage capacity, holding 50 or more discs.

MHz: Megahertz, or 1 million Hz.

Microdisplay: Type of fixed-pixel projection television that uses a chip illuminated by a lamp to produce the image--as opposed to projection technologies that use CRTs. Examples include Epson’s 3LCD, DLP and LCoS rear-projection HDTVs.

Midbass: The middle of the bass part of the frequency range, from approximately 50 to 100 Hz (upper bass would be from 100 to 200 Hz). Also used as a term for loudspeaker drivers designed to reproduce both bass and midrange frequencies.

Midrange: The middle of the audio frequency range. Also used as a term for loudspeaker drivers designed to reproduce this range.

Mini-Jack, Mini-Plug: A miniature connector, in mono and stereo versions, commonly found on portable audio equipment for headphone and line-out connections. Rare on A/V gear except for "trigger" outputs and inputs that are used to remotely activate electric screens, separate power amplifiers and subwoofers in elaborate custom home theaters and installations.

MLP (Meridian Lossless Packing): Encoding format that is able to completely reconstruct the original signal at the receiving end. No information is lost or discarded, regardless of how trivial it might be. Used to encode six channels of high-resolution audio on DVD-A.

Moire: A distracting wavy effect produced when converging lines in a video image are nearly parallel to a monitor's scanning lines.

Mono: Monophonic sound. One channel.

Monopole Speakers: One type of speaker with all drivers facing one direction. Used for precise placement of sounds. Usually used in front and center speakers.

Motion Adaptive: A processing strategy of de-interlacing line doublers and comb filters whose optimizing formula varies, depending on whether the subject matter depicted was stationary/steady or moving/changing. The best devices may vary their processing dozens of times within a single scan line. The device must digitize several video fields, save them on a rolling basis, and compare the content in small groups of pixels to determine whether subject matter was moving or not.

Motion Adaptive De-interlacing: Detects and compensates for motion in pictures, reducing contours and greatly diminishing visual noise without reducing picture detail.

MP3 MPEG-1: Audio Layer-3. Compression scheme used to transfer audio files via the Internet and store in portable players and digital audio servers.

MPEG2: High-quality audio/video compression format developed by the Motion Picture Experts Group using perceptual coding and predictive technologies similar to MPEG-1 but including a higher bit-rate and more control over the compression and technology. MPEG-2 features a bit-rate of 3.5 to 10 megabits per second as opposed to MPEG-1’s 1.5 megabits per second. The MPEG-2 format can be used to provide very high-quality images and is used with DVD, DBS (direct broadcast satellite) and HDTV (in a modified high-resolution format).

MPEG4: MPEG-4 was defined by the Moving Picture Experts Group (MPEG) and is designed to deliver DVD (MPEG-2) quality video at lower data rates and smaller file sizes. Like MPEG-1 and MPEG-2 previously did for CD-ROMs and DVDs, MPEG-4 promises to create interoperability for video delivered over the Internet and other distribution channels. MPEG-4 will play back on many different devices, from satellite television to wireless devices.

Multichannel Analog Input: (see "DVD-Audio", above). If your DVD player has the capability of playing back high-resolution DVD-Audio or SACDs, use this six-cable RCA connector set to connect to the analog multichannel input of the A/V receiver. Neither DVD-Audio or SACD hi-res discs have been proven popular.

Multiple-Rate Encoding: Instead of locking encoding at a certain constant data rate, it allows the codec to choose whatever rate is best for that portion of the recording. Usually reduces file size with proportionally less loss in quality.

Multisource: System with multiple sources. Can also be used to describe a receiver that can provide multiple different sources into different rooms.

Multi-room: System that provides audio or video to multiple areas. Usually with only one source.

Multi-zone: System that provides different sources into multiple areas simultaneously.



NAB: The National Association of Broadcasters represents the radio and television industries in Washington -- before Congress, the FCC and federal agencies, the courts, and on the expanding international front. NAB provides leadership and resources to their supporting members, to broadcasters at-large, and through ongoing public campaigns to the American people.

Native Resolution: All fixed-pixel TVs, including every flat-panel LCD and plasma, as well as rear-projection DLP and LCD TVs, have a certain number of pixels, known as the native resolution, that they use to create the picture. Most widescreen DLPs have a native resolution of 1280 x720 as an example.

N-curve: (See "Academy Curve".)

Negative Gain Screen: Material that reflects less light than a reference material. Often used for DLP and LCD projection systems.

Noise: An unwanted portion of a signal such as hiss, hum, whine, static, or buzzing.

NTSC: National Television Standards Committee The organization responsible for setting the standard for broadcast and reception of television signals in the United States. The original NTSC standards were defined in 1953, and set 525 horizontal lines of resolution, interlaced scanning and a 60Hz refresh rate. It combines blue, red, and green signals with an FM frequency for audio. The new HDTV standard will replace NTSC over the next few years.


Octave: The difference between two frequencies where one is twice the other. For example, 200 Hz is an octave higher than 100 Hz. 400 Hz is one octave higher than 200 hz.

Ohm: A measure of how much something resists (impedes) the flow of electricity. Larger numbers mean more resistance.

Optical Cable: A digital connector that carries information optically rather than electronically, which renders it unsusceptible to electrical interference.

Optical Digital Cable: Fiber optic cable that transfers digital audio signals as light pulses.

Optical (TOSLINK): TOSLINK is a standardized optical fiber connection system for consumer audio equipment, which carries digital audio streams between components such as DVD players and satellite receivers.

OSD: On Screen Display is a menu displayed on the screen with different options to help users easily adjust the display's picture.

Overscan: Overscan results in only part of the viewable image being shown on the TV or display. It's deliberately done by TV manufacturers to avoid any messy artifacts at the edges due to picture quality or an inferior power supply. But the result is that you may be missing a significant part (up to 15%) of the real picture.

Over-The-Air HD: HD programming that requires TV owners to have an HD antenna and HD-capable TV, and live in an area where digital television is broadcast.



PAL: The television standard for signal processing and broadcasting used throughout the majority of Western Europe (except France where SECAM is the standard), South America, Asia, and Oceania. The PAL standard broadcasts 625 lines of resolution, nearly 20 percent more than the U.S. NTSC standard that uses 525 lines, but at only 50 fields/second versus NTSC's 60. PAL, SECAM and NTSC are not interchangeable with each other.

Pan and Scan: A technique used in which the right and/or left edges of widescreen material is chopped off in order to fit the picture into a a narrower aspect ratio, for example the NTSC standard of 4:3 or 1.33:1. People who do this select the best part of the image to scan, and then if the whole image needs to be seen, scans across the rest of the frame.

Parametric Equalizer: with adjust-able parameters, such as center frequency and bandwidth (Q), as well as amplitude.

Passive: Not active. A passive crossover uses no external power and results in insertion loss. A passive speaker is one without internal amplification.

Passive Radiator: A radiating surface (usually similar to a conventional speaker cone) that is not electrically driven but shares the same air space in a sealed cabinet with an electrically driven loudspeaker. This arrangement is functionally similar to a loudspeaker with a vented (ported) cabinet, with the passive radiator serving the duties of the air in the port. 

Patch Cable: sometimes called a patch cord, is a length of cable with connectors on the ends that is used to connect an end device to something else, such as a power source.

Pb, Pr: Refers to the color component video signals B-Y and R-Y respectively with optimization for analog component video purposes or transmission.

PCM: (See "Pulse Code Modulation".)

Personal Video Recorder: A device that can record and play back television in digital format, as opposed to the analog format recorded by a VCR. Also called "digital video recorder."

Phase: Time relationship between signals; it's all relative.

Phono Jack: Always an RCA female connection on A/V receivers or preamplifiers for the output from a turntable's moving-magnet (MM) or moving-coil (MC) phono cartridge. Still available on up-market receivers and preamps. Don't confuse this with "Phone Plug" (or Jack), which is a larger and sturdier ¼-inch diameter connector used on consumer A/V equipment for larger headphones.

Piezo: A type of speaker driver that creates sound when a quartz crystal receives electrical energy.

Pin Connectors: Used to connect speaker wire to speakers. They may either be straight or angled. They work with spring clip, "push"-style speaker terminals, as well as with binding posts.

PIP (picture in picture): A television feature that allows you to view multiple TV channels simultaneously by creating one or more smaller displays within the larger television display.

Pixel: Contraction of picture element. The smallest element of data in a video image.

Plasma: A thin-panel video display that uses a huge array of tiny cells filled with ionized gas (plasma) which activates each cell's color phosphor. Viewable over a wide angle and capable of a brilliant image even in brightly lighted rooms. Has good contrast but tends to use more power than other types of video displays.

Plasma Display Panel (PDP): Plasma Display Panel technology is based on the same principle as the fluorescent light, using thousands of sealed, low pressure glass chambers filled with a mixture of noble gasses. Behind these chambers are colored phosphors, one each of red, blue, and green for each chamber. When energized, the chambers of plasma emit invisible UV light, which then strikes the red, green and blue phosphors on the back glass of the display making them produce visible light.

Plasma Flat-Panel Television: This flat-panel display solution consists of millions of phosphor-coated miniature glass bubbles containing plasma. An electric current flows through the screen, causing certain plasma-containing bubbles to emit ultraviolet rays, triggering the phosphor coating to produce the proper color (red, green or blue).

POP (Picture Outside Picture): A television feature that allows you to view two or more (depending on the type of POP capability the set has) TV channels simultaneously by dividing the television display into halves.

Port: An aperture in a loudspeaker enclosure that helps extend the usable low-frequency output. A ported enclosure is also called vented or bass reflex.

Power Amp: (See "Amplifier".)

Power Output: A measure, usually in watts, of how much energy is modulated by a component.

Preamplifier: A control and switching component that may include equalization functions. The preamp comes in the signal chain before the amplifiers.

Pre Outs: Connectors that provide a line-level output of the internal preamp or surround processor.

Pre Outs/Main Ins: Connectors on a receiver that provide an interruptible signal loop between the output of the internal preamp or surround processor portion of the receiver and the input of the amplifier portion of the receiver.

Pre/Pro: A combination preamp and surround processor.

Processors: Anything that processes an incoming signal in some way. Surround processors, for example, can decode a Dolby Digital signal to send to an amp so you can hear it.

Progressive Scanning: The opposite of interlaced scanning. Shows each scanning line in sequence, for a more seamless, more film-line image. Each frame of a video image is scanned complete, from top to bottom, not interlaced. For example, 480p means that each image frame is made of 480 horizontal lines drawn vertically. Computer images are all progressively scanned. Requires more bandwidth (twice as much vertical information) and a faster horizontal scan frequency than interlaced images of the same resolution. The scanning process is to "paint" all odd and even scanning lines by an electron beam every 1/60 of a second. This method reduces flicker and increases stability.

Projection: A television display system that projects the image as light onto a screen. Front projectors are located out among the audience and project on a reflective, white screen. Rear projectors are self-contained boxes that project onto a translucent screen.

Projection System: Display that projects image onto a screen.

Projection TV: Projection TVs create a miniature picture inside the projector. In rear projection systems, the image is then shone onto a screen located within the television unit itself (direct view). Front projection systems shine their images onto an external screen that is separate from the television unit.

PS/2: A port type developed by IBM for the purpose of connecting a keyboard or mouse to a PC. The PS/2 port has a mini DIN plug containing 6 pins. PS/2 ports are used so that the serial port can be used by another device. The PS/2 port is often called the mouse port.

Pulldown (3-2 Pulldown): One method of committing a 24 frame per second movie on film to 60 field per second or 60 frame per second video. Every other film frame is scanned three times and the intervening frames scanned twice to obtain video fields or frames. If you single step through a VCR recording of a movie, you will often see the three-two-three-two pattern.

Pulse Code Modulation (PCM): a way to convert sound or analog information to binary information (0s and 1s) by taking samples of the sound and record the resulting number as binary information. Used on all CDs, DVD-Audio, and just about every other digital audio format. It can sometimes be found on DVD-Video.

PVR (Personal Video Recorder). Marketing term for Video HDRs. (See "HDR".)


Q: The magnification or resonance factor of any resonant device or circuit. Also the width of affected frequencies in an equalizer. Shaped somewhat like an adjustable width bell curve.

Quick Connect: On HP microdisplay TVs, a backlit front connector panel that allows for easy setup and component changes.



RCA Connector: By far the most common small audio or video connector used on consumer audio/video equipement, with a pin (male) plug and female jack. Uses 2-conductor shielded coaxial cable. Receptacles for coaxial cables carrying line-level audio signals. Also called phono-type connectors.

Rear-Projection Television: Display that projects an image on the backside of a screen material, usually after having been reflected off of a mirror.

Receiver: An audio component with a built-in radio tuner that will receive radio broadcasts on FM or AM, switch different audio sources, as well as amplify the audio signals for delivery to loudspeakers. (see A/V Receiver above). Any component that receives, or tunes, broadcast signals, be it NTSC, HDTV, DBS, or AM/FM radio. Typically refers to the single component that includes a preamp, surround processor, multichannel amplifier, and AM/FM tuner.

Re-EQ (Re-Equalization): A feature found on THX-certified receivers and pre/pros. Movie soundtracks are mixed for theaters or far-field monitors with an expected high-frequency roll-off otherwise known as an X-curve. If these soundtracks are not re-mixed for home use, they will sound too bright when played back through home speakers or near-field monitors. Re-EQ inserts an X-curve response into the signal to compensate for this, which takes out some of the soundtrack's excess edginess or brightness.

Refresh Rate: The rate at which the picture redraws itself in one second. Usually expressed in hertz (Hz).

Resolution: The density of lines and dots per line which make up a visual image. Usually, the higher the numbers, the sharper and more detailed the picture will be. In terms of DTV, maximum resolution refers to the number of horizontal scanning lines multiplied by the total number of pixels per line, called pixel density.

    PC Resolutions:

        •VGA (Video Graphic Array) : 640 pixels x 480 pixels
        •SVGA (Super VGA) : 800 pixels x 600 pixels
        •XGA (eXtended GA) : 1024 pixels x 768 pixels
        •SXGA (Super XGA) : 1280 pixels x 1024 pixels

    TV Resolutions:

        •480i - 640 x 480 pixels interlaced
        •480p - 640 x 480 pixels progressive
        •720i/720p - 1280 x 720 pixels interlaced/progressive
        •1080i/1080p - 1920 x 1080 pixels interlaced/progressive

Resolution-Doubling Technology: A unique HP technology that projects digital images at double their resolution for improved clarity without increased cost. Also called "wobulation".

Resonant Frequency: The frequency at which any system vibrates naturally when excited by a stimulus. A tuning fork, for example, resonates at a specific frequency when struck.

Reverberation: The reflections of sound within a closed space.

Reverberation Time: The amount of time it takes the reverberation to decay 60 dB from the level of the original sound.

RF (Radio Frequency) Television signals are modulated onto RF signals and are then demodulated by your television's tuner. VCRs and DBS receivers often include channel 3 or 4 modulators, allowing the output signal to be tuned by the television on those channels. Also, laser discs used an RF signal for modulating Dolby Digital 5.1 soundtracks on some movies. This requires an RF demodulator (usually referred to as an AC3-RF demodulator) before or in the surround processor to decode the signal.

RFI (Radio Frequency Interference): is the more specific electrical interference associated with communication transmission frequency bands ranging from well below 100kHz, to well above 30GHz.

RF Modulator: a device that connects to your TV's antenna connection and provides updated connections for standard "RCA" style plugs. These are the standard connections used for VCRs, DVDs, video games and karaoke machines.

RGB: (Red, Green, Blue) Does not refer to the colored red, green, and blue connectors found on a component cable. RGB and component are not compatible and are completely different types of connections. RGB is similar to a VGA connection. Can refer to an unprocessed video signal or the color points of a display device. Together these three colors make up every color seen on a display device. This type of connection is used on computer video cards, Projectors and some old HDTV's and Set top Boxes.

RGBHV (Red, Green, Blue, Horizontal, Vertical): A video standard similar to RGB except that the horizontal and vertical sync signals are each carried on a separate line. (See "RGB".)

Ribbon Speaker: A loudspeaker that consists of a thin, corrugated, metallic ribbon suspended in a magnetic field. The ribbon acts electrically like a low-impedance voice coil and mechanically as a diaphragm.

RJ45: (See "Ethernet Cable".)

RMS (Root Mean Square): or the square root of the arithmetic mean (average) of the square's set of values. A reasonably accurate method of describing an amplifier's power output.

RoHS Certified: commonly referred to as the Restriction of Hazardous Substances Directive or RoHS, was adopted in February 2003 by the European Union. The RoHS directive took effect on 1 July 2006, and is required to be enforced and become law in each member state. This directive restricts the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment. RoHS Certified devices are free of lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ether.

RPTV: Rear-Projection Television

RS-232: Recommended Standard 232. This is the de facto standard for communication through PC serial ports. It can refer to cables and ports that support the RS232 standard.

RS-232 Interface: A serial communications interface between an electronic device and PC. The interface can be used for remote mouse control, operation by command panel, troubleshooting, service data transfer, etc.


SACD (Super Audio Compact Disc): (See "DVD-Audio", above): an enhanced, high-resolution digital multichannel audio standard developed by Sony/Philips that uses DSD (Direct Stream Digital) audio encoding. Requires an SACD Player. Multichannel audio also requires a controller with six-channel analog or proprietary digital inputs for full playback. You'll need a bundled, shielded 6-cable RCA connector set of cables to play back SACD to the A/V receiver as well as an SACD-compatible DVD player. Most inexpensive (less than $150) DVD players will not play SACD or DVD-Audio discs. Only "Universal" DVD players will play these formats as well as conventional DVDs and CDs.

Sampling: The process of converting an analog signal (such as a picture or a soundtrack) into digital form. In the case of a picture, a large number of small, evenly spaced areas are taken and each represented as one or more numbers for brightness (luminance) and color. These areas are referred to as picture elements or pixels. The more samples are taken, the more accurate (with higher resolution) an image can be reconstructed from the samples. For DVD, the image is 720 samples wide by 480 samples high for a total of 345,600 samples (may vary slightly). Even analog TV has sampling -- each scan line is a discrete (as in digital) sample in the vertical direction although it is continuous (analog) in the horizontal direction.

Sampling Frequency: How often a digital sample is taken of an analog wave. The more samples taken, the more accurate the recording will be. You need to sample at a minimum of twice the highest frequency you want to capture. For example, the 44.1-kilohertz sampling rate of a CD cannot record sounds higher than 22.05 kilohertz.

Scaler/Scaling: The reformatting of video or digital pictures to occupy a different number of scan lines or a different horizontal or vertical pixel count. Also referred to as "resampling". This is done to zoom an image on the screen without spreading out the existing scan lines, or to change the video from one format to another, for example HDTV to NTSC or NTSC to SECAM. A video scaler is designed to change the resolution of an input device/source to match the resolution of the output device/display. For example, if your display is a 1080p LCD HDTV, you can connect a 480p DVD player to a 1080p video scaler and it will upscale the image to display at 1080p on your TV.

Scan Lines: The lines drawn by an electron gun in a CRT system to make up the picture. Drawn horizontally, from left to right, starting at the top left and working to the bottom right.

Screen: What the picture is projected onto. The screen is more important when it comes to front projectors, when the screen must be bought separately.

SDTV (Standard-Definition Digital TV): Lower resolution subset of the ATSC's DTV system. 480i signal (480 interlaced scan lines) presented 30 times per second, is typically accepted as an SD signal. This is the standard of resolution for all conventional DVDs. Many DVD players may be set to output "progressive scan" 480p signals, which remove the scanning lines producing a smoother film-like picture. Digital broadcasters can offer multiple sub-programs at SDTV quality, as opposed to one or two HD programs. Digital satellite and digital cable often refer to the majority of their programs as SDTV, somewhat erroneously, as neither system has anything to do with DTV, though both, technically, consist of a digital 480i signal.

Sealed: (See "Acoustic Suspension".)

SECAM: Sequential Couleur avec Memoire is the television broadcast standard in France, the Middle East, and most of Eastern Europe. SECAM uses a similar timing and resolution to PAL, and is one of three main television standards throughout the world.

SDI (Serial Digital Interface): An SMPTE standard for digital video transmission over coaxial cable. The SDI signal can also contain up to four independent digital audio signals along with the video signal. Two variations of SDI standard exist, based on the data rate: standard-definition (SD)-SDI and high-definition (HD)-SDI. The SDI standard is widely used in broadcasting and the video production industry because of the ability to transmit video signals over long distances with no loss of information.
A set of standards for digital transmission of video over 75 ohm coaxial cable preferably using BNC connectors.. For video it usually uses a 270 megabyte per second data transmission rate and it supports the standard NTSC based video formats and ATSC video formats. It is suitable for transmission over 100 feet contrasted with DVI and HDMI which are limited to about 30 feet.

Sensitivity: A measurement (in dB) of the sound-pressure level over a specified frequency range created by a speaker driven by 1 watt (2.83V at 8 ohms) of power with a microphone placed 1 meter away.

Serial Port: A data I/O port on the computer enabling other devices or computers to link with the computer. Also referred to as RS-232C or COM port.

Set-top box (STB): External receiver that converts broadcasts (such as analog cable, digital cable, or DTV) for display on a television. HDTV-ready TVs must be connected to a compatible HDTV tuner set-top box in order to receive digital television programs.

Signal-to-Noise Ratio: A comparison of the signal level relative to the noise level. Larger numbers are better.

SMPTE: Society of Motion Picture and Television Engineers.
A global organization, based in the United States, that sets standards for baseband visual communications. This includes film as well as video standards. SNMP Simple Network Management Protocol, SNMP is called “Simple” in a relative way in the sense that they tried not to add unnecessary complexity when it was developed. SNMP management data is available from SNMP agents and is queried from SNMP capable consoles or test tools.

Snake Cable: A name given to individually shielded or individually shielded and jacketed, multi-pair audio cables. Used in the connection of multi-channel line level audio equipment.

Soft-Dome Tweeter: A tweeter that uses a soft fabric or plastic dome as the radiating diaphragm.

Soft-Matte: A projection technique where plates block out the top and bottom of the picture as it is being projected in order to achieve a widescreen effect. The opposite is Hard-matte.

Sony Dynamic Digital Sound (SDDS): An 8-channel sound format used in commercial movie theaters. The 8 channels are: Left Front, Left/Center Front, Center Front, Right/Center Front, Right Front, Left Surround, and Right surround. The sound is encoded in between the sprockets on the film. No follow-up has been announced for home theater.

Soundfield: The total acoustical characteristics of a space, such as ambience; number, timing, and relative level of reflections; ratio of direct to reflected sound; RT-60 time; etc.

Soundstage: The area between two speakers that appears to the listener to be occupied by sonic images. Like a real stage, a soundstage should have width, depth, and height.

Source: A component from which the system's signals originate. Can be an audio, video, or audio/video device. DVD player, AM/FM tuners, and VCRs are sources.

Spade Connectors: Another type of connector used to connect speaker wire to a speaker. Recognized by a forked piece of metal, designed to hug the collar of a 5-way binding post terminal. The spade is then secured by tightening the binding post's cap. Spade connectors give you very secure contact.

SPDIF (Sony/Philips Digital Interface): A digital audio interface, most often used with an RCA connector.
SPDIF is a digital interface designed to enable digital equipment to transfer digital information with minimal loss.

Speaker: A component that converts electrical energy into acoustical energy.

Speaker Cable: Available in various gauges or wire thickness, designated by "AWG" followed by a number (e.g., AWG12 is 12-gauge speaker cable). The lower the number, the thicker the cable and the less resistance there is to the passage of amplified audio signals (AWG12 is thick; AWG18 is fairly thin) from you're A/V receiver or amplifier. All speaker cable is 99.9% oxygen-free copper. You'll need one 2-conductor cable for each speaker in your home theater system, except the subwoofer. A 5.1-channel system will require five separate speaker cables plus a single coaxial cable for the subwoofer (see Coaxial, above); a 7.1-channel system, seven cables plus a single coaxial sub cable. Choose the speaker cable gauge by the length of the cable run from the receiver/amplifier to the speaker. For runs up to 20 feet, 14-gauge is fine. Use 12-gauge speaker wire for long runs up to 60 feet. Good generic speaker cable can be purchased in bulk. Speaker cable does not impart musical qualities to the movement of electrons. All copper cables of sufficiently thick gauge sound identical.

Spider: Part of a loudspeaker driver's suspension that helps center the diaphragm and returns it to rest after being moved by an energized voice coil.

SPL: Sound-Pressure Level. Measured in dB.

Splitter: (See "Distribution Amplifier".)

SRS Dialog Clarity Enhancement: An audio technology that makes movie and television dialogue crisper and more clearly articulated. Also a feature of SRS TruSurround XT.

SRS TruBass: An audio technology that enhances low-frequency sound. Also a feature of SRS TruSurround XT.

SRS TruSurround XT: A three-dimensional, high-definition audio technology that produces the effect of surround-sound with as few as two speakers. Voices are more accurate, bass is richer, and sound is overall fuller and more dramatic.

SRS WOW: An audio technology that strengthens voices and creates rich bass without the need for a subwoofer.

Subwoofer: A speaker designed to reproduce only very deep bass frequencies from 100 Hz to 20 Hz or lower. Usually contains its own dedicated amplifier. It is the ".1" channel of Dolby Digital 5.1 and DTS surround formats.

Surround Channels: A sound field that is 3-dimensional, intended to envelop the listener, rather than a stereo soundstage mainly in front of the listener. Normally achieve with two discrete surround speakers placed (ideally) to each side of the listening area, used to convey ambient sound effects, special effects and musical enhancement for Dolby Digital 5.1 and DTS surround soundtracks. Many Dolby Digital and DTS decoders in modern A/V receivers will extract and simulate two additional Back or Rear surround channels for 6.1-channel and 7.1-channel surround setups.

Surround Sound: A sound system arrangement designed to place the listener in the center of the sound.

Suspension: The elements that hold a loudspeaker driver's moving parts together, allows them to move, and helps return them to rest. Most commonly, these include the flexible surround around the outer rim of the driver and the spider on the underside of the diaphragm. (See "Spider".)

SVGA: Super VGA is an extension to the original VGA standard, and allows resolutions of 800x600.

S-VHS: Super VHS. Enhancement to regular VHS that offers improved luminance resolution. (400 lines or so.)

S-video: A small multi-pin connector cable that carries the chrominance (color) and luminance (brightness) video information separately, resulting in sharper, more colorful images. Not capable of carrying HD video signals but superior in picture clarity to composite video connections. Use this connector for better image quality if your TV, A/V receiver or VCR has S-video inputs and outputs. In contrast to composite video, S-Video has a sharper picture. Nowadays, DVD players, some VCRs, and many high-end televisions all support S-Video.

S-Video Connection: Common video connection that provides better picture than composite by transmitting the luminance and chrominance portions of a video signal separately.

SXGA: Super XGA resolution is 1280x1024 pixels

SXGA+: Super XGA+ resolution is 1400x1050 pixels. It is a hybrid between SXGA and UXGA found on some LCD screens for laptop PCs.


Tactile Transducer: A device that turns electrical energy into mechanical energy, usually used to shake the seating in a theater. Effective in providing visceral impact without increasing the system's actual SPL level.

Terrestrial HD: (See "over-the-air HD".)

THD: Total Harmonic Distortion

THX: Certification program for home theater equipment. Uses some proprietary features, but mostly assures a base quality level for a given room size. (See THX Select or Ultra.) Is compatible with any and all soundtrack formats. Stands for either Tom Holman's eXperiment, after the engineer who drafted the original standard, or is named after the company's founder George Lucas' first movie, THX 1138. Nobody can agree on which.

THX Select: Certification program for speakers and receivers that assures a base level of quality and performance when played in a room that's between 2,000 and 3,000 cubic feet.

THX Surround EX: This is built to further extend Dolby Digital Surround EX (DD-EX). This could be considered a 7.1 channel system. As opposed to DD-EX, which has an added channel in the center rear, THX-EX puts 2 more channels in the rear, so there is a front left, front right, front center, listening position left, listening position right, rear left, rear right. It uses Dolby Digital 5.1 as a base and matrixes in the extra 2 channels into the rear channels similar in fashion to Dolby Pro-Logic and Matrixed Surround. It is going to be available exclusively in THX Ultra certified products.

THX Ultra: Certification program for speakers, receivers, and amplifiers that assures a base level of quality and performance when played in a room that's greater than 3,000 cubic feet.

THX Ultra 2: The newest certification from THX, THX Ultra 2 requires amplification for seven channels, boundary compensation for subwoofers, and stricter requirements for amplifiers and speakers than THX Ultra. Dipole speakers are used for the side surround channels. Monopole speakers are used for the surround back channel and are placed next to each other. The Ultra 2 processor accommodates both 5.1 EX/ES soundtracks, as well as multichannel audio recordings by directing ambient sounds to the dipole speakers and discrete effects/sounds to the back channels.

Toslink (see fiber-optic, above): A plastic-fiber optical cable for carrying digital audio signals in optical form, as pulses of light, from a DVD player or CD player to an AV receiver. Will carry as many as six separate digital channels of audio for Dolby Digital 5.1 or DTS surround soundtracks.
TOSlink stands for "Toshiba Link", and is Toshiba's brand name for optical digital audio cables.

Transducer: Any device that converts one form of energy into another form of energy, specifically when one of the quantities is electrical. Thus, a loudspeaker converts electrical impulses into sound (mechanical impulses), a microphone converts sound into electrical impulses, a solar cell converts light into electricity, etc.

Transmission Line: A (sub)woofer cabinet design where the driver is mounted at one end of a tube with the same diameter as the radiating area of the driver and a length of 1/4 wavelength of the 3dB down frequency. This "tube" may or may not be round and may be folded to decrease the size of the cabinet.

TRS Connector (Tip, Ring, Sleeve Cable): an analog cable used to connect audio devices. It typically comes in 1/4" and 1/8" diameters. It is balanced, as opposed to the unbalanced signal of RCA cables.

TV Tuner: TV sets all come with built in tuners, which select the specified channel out of all of the channels broadcast, and convert it into a baseband (non-modulated) video signal for display. Plasma Display TVs may require a separate tuner, which may be a satellite or a cable set-top box. (See Receiver.)

Tweeter: A speaker driver designed to reproduce high frequencies; usually those over approximately 5,000 to 10,000 Hz.


UHDV (Ultra High-Definition Video): A next-generation HD format developed by the Japanese Broadcasting Corporation. Its resolution is 16 times greater than standard HD video, but it requires several terabytes of storage and a 450-inch diagonal screen to enjoy.

UL Listed: Stands for "Underwriters Laboratory". It tests electrical components and equipment for potential hazards. When something is UL-listed, that means that the UL has tested the device, and it meets their requirements for safety - i.e.: fire or shock hazard.

Underscan: Condition when the picture size is adjusted so that strips of unused screen area are along all borders. Computer users sometimes leave their monitors adjusted this way to guarantee that material such as the "start button" in the lower corner of the Windows screen does not disappear beyond the edge. Also on some TV sets the edges of the picture suffer distortion when extended all the way to the picture tube edge. (See also "overscan".)

Uniformity: Even distribution across a given space. In video, uniformity can refer to the distribution of light (hot spotting) or color.

Unity Gain: Output that equals the input. Unity gain screen material reflects as much light as the reference material. Has an even dispersion of light.

Universal Remote Control: Remote that has the commands of numerous brands stored into memory and can control several different devices simultaneously. Not all are compatible with all brands and models of TVs, VCRs, DVD Players and A/V receivers.

Upscale/Upconvert: In DTV, the conversion from a lower-resolution input signal to a TV capable of displaying higher resolutions, such as from an SDTV 480p signal to an HDTV 1080i native display. To convert a video format to a higher resolution or higher quality form. For high-definition television, it is used to describe the process of reformatting a SDTV (480i/480p) signal to an HDTV format (1080i). This may not actually increase picture resolution, but allows the program to be accepted through the set's HDTV inputs.

USB: Universal Serial Bus. An external peripheral interface standard for communication between a computer and external peripherals over a cable using bi-serial transmission.

UXGA: Ultra XGA - describes 1600x1200 pixel resolution.


VAS: The volume of air that offers the same degree of restoring force on the loudspeaker driver's cone as that of the cone's suspension.

VCR: (See "Video Cassette Recorder".)

VCR Plus: VCR feature that, once programmed, allows the user to input the TV guide code for a given program into the VCR, which then automatically sets itself to record that program.

Vented: (See "Port" or "Passive Radiator".)

Vertical Resolution: Number of horizontal lines that can be output by a video display. Higher resolutions result in better quality pictures. Television resolution is often stated in vertical resolution, for example the NTSC (analog) television standard used in the United States has a vertical resolution of 525 - there are 525 horizontal lines to make up the image. It should be noted that DVD and some digital broadcasts (satellite, digital cable) are the only sources that actually provide the maximum vertical resolution (or at least close to it). Vertical resolution for high definition television is set at either 1080 lines (1080i = 1080 interlaced lines) or 720 lines (720p = 720 non-interlaced lines).

VESA: Video Electronics Standards Association - An association whose mission is to promote and develop timely, relevant, open display and display interface standards, ensuring interoperability, and encouraging innovation and market growth.

VGA: Video Graphics Array is a video standard that allows for resolutions up to 640x480 with up to 16 colors, or 320x200 resolution with 256 colors. Today, however, VGA refers to a 640x480 format. Higher resolutions have now mostly replaced VGA, but VGA compatibility remains an important part of most graphics cards.

VHS: Vertical Helical Scan (or as JVC calls it, "Video Home System"). Widely used method of recording audio and video electrical signals onto magnetic tape.

Video Cassette Recorder: Device that records audio and video electrical signals onto magnetic tape (aka videotape recorder).

Video Distribution Amplifier: Also called Video splitter. This type of device will take the output of one video source and send an identical signal to two or more connected displays. (See "Distribution Amplifier".)

Video Converter: A device that changes the video connection from one format to another. For instance, Component Video into HDMI. (See "Converter".)

Video Matrix Switch: (See "Matrix Switch").

Video Scaler: Electronic device used to perform scaling, usually with a choice of scalings not necessarily an even multiple or fraction of the original scan line or pixel count.

Video Splitter: (See "Distribution Amplifier".)

Video Switch: also called a router, or switcher. An electronic device capable of interconnecting many components to be viewed one at a time simultaneously on one or more displays. Input sources include computers, cameras, DVD players, etc. Destinations include projectors, monitors, and computers etc. Matrix switchers route any input to any combination of outputs. Different matrix switchers can route different signals, such as composite video, S-Video, stereo audio and mono audio. A video switch minimizes the amount of cables going from the sources directly to the TV because all sources are connected to the switch with only one cable going from the switch to the display. For more advanced switching capabilities, such as being able to view more than one source on multiple displays (any input on any output), please see "Matrix Switch".

Viewing Angle: The maximum angle at which an image can be viewed from an off-center point.

Visual Choice: A feature on HP micro-display TVs that permits quick, simple change between video sources via remote control and onscreen view.

Visual Fidelity: An HP picture-processing technology that analyzes every pixel of every image from every video source for noise reduction, color enhancement, motion compensation, and detail enhancement to deliver a spectacular picture.

Volt: The unit of electrical potential, or difference in electrical pressure, expressing the difference between two electrical charges.


Watt: A unit of power or energy. One horsepower is equal to 745.7 watts.

Widescreen: Programming and video systems that incorporate an aspect ratio wider than the conventional 4:3 television screen. Typically refers to TVs in the 16:9 aspect ratio.

Wire Gauge: refers to the diameter of a wire. The higher the gauge number, the thinner the wire. Thicker wire will be able to maintain bass tones better, and over a longer distance than thinner wire. Thicker wire also tends to deliver fuller, cleaner sound in general, compared to thin wire. This is because as a signal travels through wire, resistance leads to signal degradation. A 12 wire gauge is a typical choice for high quality entertainment systems, while some prefer a 10 gauge wire for the subwoofer, or bass speaker.

WMA (Windows Media Audio): Developed by Microsoft, WMA is a sound-file format that is even smaller than MP3. WMA offers near-CD-quality sound at an encoding rate of only 64Kbps (as opposed to MP3's 128Kbps), cutting the file size in half. Optional copyright protection is included in the WMA code, allowing the owner to restrict the use of protected material.

Wobulation: A unique HP technology that projects digital images at double their resolution for improved clarity without increased cost. Also called "resolution-doubling technology."

Woofer: A speaker driver designed to reproduce low frequencies.

Word Length: The sampling rate determines how often an analog wave is sampled; the word length determines the resolution of the sample. The larger the word length, the more accurate the sample as a whole. A 16-bit word length (CD) allows 65,536 different level or volume steps that can be chosen for each sample.

Wow-and-Flutter: A measurement of speed instability in analog equipment usually applied to cassette transports and turntables. Wow is slow-speed variations, and flutter is fast-speed variations. Lower percentages are better.


X-Curve: An intentional roll-off in a theatrical system's playback response above ~2kHz at 3dB per octave. A modern convention (standardized between 1975 and 1984) specified in ISO Bulletin 2969, it is measured at the rerecording position in a dubbing stage or two-thirds of the way back in a movie theater. Pink noise should measure flat to 2kHz and then should roll-off above that. Home THX processors add this roll-off, when engaged, so that a home video soundtrack will have the same response as it would in a theatrical setting.

XGA: An analog computer video format with 768 visible scan lines each normally representing 1024 pixels across.

X-Over: (See "crossover".)

XLR Connector: a three-pin electrical connector. XLR  plugs and sockets are used mostly in professional audio and video electronics cabling applications, often for microphones. (See "Balanced Connector".)


Y/Pb/Pr: Also called "component video". Generally used where a digital TV signal source is used. The video signal is separated into its component parts of brightness and color differentials. The most advanced method for interconnecting decoded video data. Also sometimes referred to as Y/Cb/Cr where a video signal is separated into components of brightness and color. Usually recognized by the red, blue, and green colored connectors on the cable ends. Not the same thing as RGB. RGB is a completely different type of connection, similar to VGA.

Y/C: Abbreviation for luminance/chrominance, also called S-video signal. Color and detail signals are kept separate, thus preventing composite video artifacts. Cable uses four-pin connector. Used with S-VHS VCRs, DVD players, Hi-8, and DBS receivers.


Zone: One or more rooms powered by one or more amplifiers, which are all fed by one source. A home can be divided into multiple zones, which can play multiple sources, even though several rooms (say, the kitchen, dining room, and living room) all play the same source.

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