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Home :: Home Theater Glossary

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Home Theater Glossary

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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.

3:2 Pull-Down or 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.

3-D color managment system	An auto-adjusting tool that ensures accurate color displays.

3D 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.

3D 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.

3D 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 suround 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.
A
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.

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

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

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

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.

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 the width to the height of a direct-view picture or projected image. The standard aspect ratio for HDTV is currently 16:9 (rectangular, wide screen image). The National Television Standards Committee (NTSC) standard for analog television broadcasts is 4:3 (traditional square format).

ATSC	An acronym for Advanced Television Standards Committee. An advisory group that produced the table of 18 recommended transmission formats for Digital Television (DTV) broadcasting in the United States.

ATSC HD	Advanced Television Systems Committee, an international organization that develops digital television standards. Also see "over-the-air HD".

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

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

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.
B
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.

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	A vented speaker enclosure that utilizes controlled rear radiated sound waves.

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

Bipolar	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 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.

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.
C
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.

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. An association of manufacturers of consumer electronics products.

Center Channel	The center speaker in a home theater setup. 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.

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.

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.

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

Coaxial:	1) A speaker typically with one driver in the middle of, and on the same axis as, another driver. 2) An audio or video cable with a single center pin that acts as the hot lead and an outer shield that acts as a ground.

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

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 most live 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.

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

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	Component Video is the best method of delivering quality video (RGB) in a format that contains all the components of the original image. Composite Video. Composite video is the standard method of connecting video equipment. Composite video combines picture signal, including vertical and horizontal blanking and synchronizing signals.

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).

Composite	In composite format, all video information is combined into one signal and broadcast through one RCA-type jack.

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.

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

CRT projection	CRT (Cathode Ray Tube) projection is a display solution widely used in televisions and computer monitors. The tube in a CRT system is a vacuum through which electrons pass, striking a phosphorescent surface on which the projected image is created. CRT projectors output three identical images in red, green and blue. These are then combined to create the final projected image.

CRT Projector	One type of front projector. It consists of three tubes each putting out one color: red, green, and blue. They offer brightness and detail, but are difficult to setup, and convergence is required about two times a year.

Cut	To reduce, lower; opposite of boost.
D
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	A loudspeaker configuration developed by and named for Joe D'Appolito, in which a high frequency driver, or tweeter, is positioned between two midrange or low frequency drivers that each cover the same frequency range. Depending on the exact implementation the speakers can be positioned with a vertical and/or horizontal orientation. In either case the two midrange drivers serve a couple of purposes: they combine to create a larger effective woofer or midrange driver size, and they also serve to control the dispersion of the tweeter.

Dark video enhancement	Enhances details in dark scenes.

DBS	Direct Broadcast Satellite. Term that replaced DSS to describe small-dish, digital satellite systems such as DirecTV and Dish Network.

Decibel (dB)	The measure of the power ratio of two signals. In system use, a measure of the voltage ratio of two signals, provided they are measured across a common impedance.

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	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 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 Light Processing™ technology / 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.

Digital Micromirror Device (DMD)	The Digital Micromirror Device is an optical semiconductor chip populated with up to a million or more hinged, microscopic mirrors; in a DLP® projection system, these mirrors operate as optical switches to create a high resolution, full-color image.

Digital Television (DTV)	DTV refers to the three types of digital television including Standard Definition Television (SDTV) 480p or 480i, Enhanced Definition TV (EDTV), and High Definition Television (HDTV) 720p or 1080i.

Digital Theater Systems	See DTS

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 followup 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 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.

DVD RAM	A type of DVD media designed for storage and archiving of user information. Unlike most other current DVD formats, DVD-RAM is designed to be written and rewritten by end users, requiring no special equipment beyond a DVD-RAM drive. In this way they work a lot like CD-RW discs, only hold much more information.

DVD-A	Digital Versatile Disc-Audio. Enhanced audio format with up to six channels of high-resolution, 24-bit/96-kHz audio encoded onto a DVD, usually using MLP lossless encoding. 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-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. See D-Theater

DVI	Digital visual interface. Video only omnidirectional digital connectivity standard that conveys an uncompressed digital signal from a digital source. Used on only some HDTVs, projectors, Set-top boxes and receivers.

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.

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.
E
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.

Electronic program guide	A program menu on HP entertainment products, such as the Digital Entertainment Center and Media Center PC, that displays chronological, and automatically updated, program listings.

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.

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.

EX	See Dolby EX.

External Crossover	A standalone unit. See crossover.
F
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 Cable	Glass, plastic, or hybrid fiber cable that transmits digital signals as light pulses.

FireWire	See IEEE 1394.

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	Front projection is 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.
G
Gain	Increase in level or amplitude.

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.
H
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.

HD DVD (high-definition DVD)	A next-generation optical disc format developed for high-definition video recording and rewriting. Types (red or blue laser) and storage capacity of HD DVDs vary. They include blue-laser DVD, Blu-ray disc, HD DVD-9, and EVD.

HDCP	High-Bandwidth Digital Content Protection. Created by Intel, HDCP is used with HDTV signals over DVI and HDMI connections and on D-Theater D-VHS recordings to prevent unauthorized duplication of copyright material.

HDMI	High Definition MultiMedia Interface is the next generation of DVI (Digital Visual Interface). It includes the DVI digital video signal, and multi-channel digital audio signals on a single cable.

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

HDTV	High-Definition Television. The high-resolution subset of our DTV system. The FCC has no official definition for HDTV. 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.

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.

High Definition Television (HDTV)	HDTV is a new television standard that uses digital signals rather than the current analog broadcast standard. HDTV signals contain over 700 horizontal lines of resolution, compared to the 525 lines of resolution that analog provides. HDTV is also geared toward a rectangular wide screen format (16:9) for a true theater-like experience. images are digitized and compressed before signal transmission to enable their tremendous quantity of information to pass through easily. The signals are then decompressed when they reach the television. From football to sitcoms, the result is a clear, crisp picture that brings every broadcast to life with more detail and truer color than any other picture format can offer.

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.

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.

Hz	Hertz or cycles per second. Something that repeats a cycle once each second moves at a rate of 1 Hz.
I
IEEE 1394	Networking standard for PCs. Combined with 5C copy protection, is used as a two-way connection to transfer the MPEG-compressed digital bitstreams between consumer electronics items, including HDTV tuners and displays, D-VHS recorders, DVD players, and DBS receivers. Also called FireWire, iLink, …

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 cable or wire running between two pieces of A/V equipment. 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 Scanning	Scan method used by the traditional television technology and the 1080i HDTV format. As opposed to progressive scanning in which the CRT's electron beam scans or "paints" all lines at once, interlaced scanning TVs paint odd-numbered lines in succession, then go back and fill in the remaining even-numbered lines.

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

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.
J
K
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.
L
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. 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

Lenticular	Outer screen on Epson Livingstation HDTVs characterized by a vertical pattern of ridges and valleys. Blackstripes are applied to the lenticular at a 0.098mm pitch to provide image contrast, high diffusion and high picture density.

Letterbox	One technique for accommodating widescreen programming on a standard 4:3 screen. Letterboxing presents the widescreen picture with black bars across the top and bottom.

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/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.

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.

Luminance	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.
M
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.

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.

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.

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 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.

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.

Multiroom	System that provides audio or video to multiple areas. Usually with only one source.

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

Multizone	System that provides different sources into multiple areas simultaneously.
N
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	Random, unwanted interference with the signal to which you're trying to watch or listen. In audio, noise takes the form of hiss or static. In video, noise is picture "snow," random flecks or specks of unwanted color.

NTSC	NTSC is also the video-transmission standard used in the western hemisphere, Japan, and other Asian countries. NTSC standards are 525 lines of resolution transmitted within a 6MHz channel at 30fps.
O
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.

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.
P
PAL	The standard by which TV is broadcast in Europe. It has a theoretical maximum resolution of 625 lines. Also has an aspect ratio of 4:3/1.33:1, and in some places 16:9/1.78:1.

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. Pepople 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.

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.

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

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	A contraction of "picture element". The smallest element of data in a video image.

Plasma	Flat-panel display technology that ignites small pockets of gas to light phosphors.

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.

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

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

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-like image. 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.

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.
Q
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.
J
RCA Jacks	Receptacles for coaxial cables carrying line-level audio signals. Also called phono-type connectors.

Rear Projection TV	A method of projection that combines a projector and viewing screen into one television unit.

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	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	Short for 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	A measure of video signal detail for source material, transmission channels, recorders and displays, generally described either in terms of lines of resolution, or pixels.

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

RF	RF signals vary widely depending on your cable and satellite provider and the type of signal being broadcasted.

RGB	Red, Green, Blue. 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.

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.

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.

RPTV	Rear-Projection Television
S
SACD	Super Audio CD. Enhanced audio format with up to six channels of high-resolution audio encoded using DSD. Requires an SACD player. Multichannel also requires a controller with six-channel analog or proprietary digital inputs for full playback.

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.

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 Television. Lower resolution subset of the ATSC's DTV system. 480i is typically accepted as an SD signal. 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.

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.

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.

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 followup 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. DVD player, AM/FM tuners, and VCRs are sources.

SPDIF (Sony/Philips Digital Interface)	A digital audio interface, most often used with an RCA connector.

Speaker	A component that converts electrical energy into acoustical energy.

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.

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 subwoofer is an individual speaker commonly found in home theater sound systems that processes bass sounds as low as 15 hertz.

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.

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

S-video	In S-video format, color and luminance data are separated, resulting in sharper, more colorful images. This format is commonly available on S-VHS video players and DVD players.

S-Video connection	Common video connection that provides better picture than composite by transmitting the luminance and chrominance portions of a video signal separately.
T
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. People often disagree 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	A type of optical cable used to connect A/V components, distinguished by its plug shape.

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.

Tuner	See Receiver.
U
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.

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	Simplifies operation by also controlling many brands of TVs, VCRs, DVD players and A/V receivers. (not all are compatible with all brands and models.)

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.
V
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.

VHS	Vertical Helical Scan (or as JCV 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).

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

Visual Choice	A feature on HP microdisplay 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.
W
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.

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
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.

X-over	See crossover.
Y
Y/C	Abbreviation for luminance/ chrominance, aka 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.

Y/Pb/Pr	See component video.
Z
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.