Glossary of Terms
If you have a more than passing interest in both cinema and home theatre sound reproduction, itÕs likely that you will encounter most, if not all, of the following terms:

Acoustics: Characteristics like sound reflection and absorption that differentiate one environment from another, such as a living room from a concert hall.

AC-3: Audio Code 3. This is simply another name for Dolby Digital 5.1.

Algorithm: A formula or set of steps used to simplify, modify, or predict data. Complex algorithms are used to selectively reduce (compress) the high digital audio and video data rates. Algorithms are formulated to selectively reduce the data rate without affecting picture quality.

Ambiance: Low level sounds that set a mood or suggest the character of a particular place

Analog: The technology in use for more than 50 years to transmit conventional radio and TV signals. Vinyl recordings and most cellular phones are examples of analog technology.

Anamorphic: The DVD format is specially designed to support widescreen displays. Widescreen 16:9 video can be stored on the DVD disc in anamorphic form, meaning the picture is squeezed horizontally to fit the standard 4:3 rectangle, then unsqueezed during playback.

This anamorphic squeezing results in less of the picture being wasted on the black letterbox mattes. DVD has a frame size designed for 1.33 display, so the video still has to be made to fit, but because it's only squeezed horizontally, 33% more pixels (25% of the total pixels in a video frame) are used to store active picture instead of black. Anamorphic video is best displayed on widescreen equipment, which stretches the video back out to its original width.

Anamorphic video can be converted by the player for display on standard 4:3 TVs in letterbox or pan & scan form. If anamorphic video is shown unchanged on a standard 4:3 display, people will look tall and skinny as if they have been on a crash diet. The setup options of DVD players allow the viewer to indicate whether they have a 16:9 or 4:3 TV.

Artifacting: Artifacting is a result of the compression that a film has to subjugate itself to when making the translation to a home-theater format. Because DVD has restricted disc space (7 gigs and up based on the DVD) movies need to be compressed to fit on the DVD. If done improperly, this can cause artifacting or other video imperfections to happen, which is basically a result of the compression. It causes undesirable elements or defects in a video picture. Most common in digital are macroblocks, which resemble pixelation of the video image, and pops and clicks in audio.

Aspect Ratio: The ratio of a television picture width to height. In NTSC video, the standard is 4:3. In HDTV and SDTV widescreen video, it is 16:9. Aspect ratios are simply the width to height ratio of how a movie or television show is filmed. For example, in the United States, television shows are filmed in 4:3 aspect ratio. By doing the division, you can calculate that on a standard television. The screen width is 1.33 times the height. On a widescreen TV the ratio is expanded to 16:9. Keep in mind however, that not all theatrical movies are filmed in 16:9 (or 1.78 aspect ratio). Many movies are filmed in 1:85, 2.15 or 2.35 widescreen. Movies filmed in an aspect ratio greater than 16:9 will result in black bars on the tops and bottom of the screen on a widescreen television. The 16:9 aspect ratio is also the standard for the new HDTV format.

Atmospherics: Background sounds, such as wind, rain, or traffic noise, which add to the reality of a scene. These sounds are sometime recorded right at the shooting location, creating a wild track which is later mixed into the final sound-track.

Bandwidth: The complete range of frequencies over which a circuit or electronic system is allocated to function. In transmission, the U.S. analog and digital television channel bandwidth is 6 MHz.

Bandwidth (pixel. Freq.): In monitor terms it is the amount of pixels that can be displayed per second.

Bi-Amping: Bi-amping refers to the use of two separate amplifier channels connected directly to individual loudspeaker drivers optimized to reproduce a particular frequency range. For example, one amplifier channel would be connected directly to a tweeter for high frequency reproduction, another to a woofer for bass reproduction. Bi-amping requires an electronic crossover to divide the wide range audio signal from a preamplifier before that signal ever gets to the amplifiers. The advantages of traditional bi-amping are significant. Damping factor (a measure of the amplifier’s ability to control the back-and-forth motion of the driver) increases, intermodulation distortion goes down, and effective amplifier power is increased dramatically.

Bi-Polar, Bi-Pole (Speaker): Bi-polar refers to speakers with drivers that are fired in two different directions, but are in phase causing an increase in bass output. I this type of speaker the drivers can be in the front and back of the speaker, side firing, or at 90º angles from one another. There are also speakers which function as both bipolar and dipolar. This can be adjusted using a switch.

Bi-Wiring: Bi-wiring refers to separate wire runs from a common amplifier output to two different inputs on the same speaker. This requires a speaker specifically designed with bi-wiring in mind as the speaker’s passive crossover must be designed to allow this. And the speakers must have two sets of external binding posts connected by removable jumpers or "bus bars."

Closed Captioning:Text stream included in broadcast signal that provides narrative description of dialogue, action, sounds, and other elements of the picture. Most often used by the hearing impaired and in environments where audio is undesirable (such as in restaurants).

Component Video: A video transmission method. Better than composite video and s-video, equal to RGB video. Component video uses three (RCA-jack type) cables to distribute the red, blue and green portions of a video transmission separately. Component video is typically used with DVD players and HDTV systems.

Composite video: This is the worst way you can hook the DVD player up to your television, whereas RGB and S-VIDEO splits the signal up into its components a composite signal is exactly that - composite. When a television displays a composite signal, it uses its comb filter to process the image and then separate the colors, a stage bypassed and not required by RGB or S-VIDEO.  It’s basically an encoded video signal, such as NTSC or PAL video, which includes both horizontal and vertical synchronizing information. In other words, Composite video utilizes one (RCA-jack type) cord to transmit all picture information.

Compression: Reduction of the size of digital data files by removing redundant and/or non-critical information ("data" being the elements of video, audio and other "information"). Digital TV in the U.S. would not be possible without compression.

DAB: Digital Audio Broadcasting: This is digital radio that both the BBC and independent stations are starting to use. It offers vastly improved sound and a choice of many more stations.

Digital audio:This refers to the coaxial and optical outputs on the rear of the player that send the digital audio stream (either Dolby Digital, DTS or PCM) to the amplifier.

Digital outputs:Digital Outputs are what send the Dolby Digital or DTS encoded audio track to a suitable amplifier. There are two types - coaxial or optical.

Digital (AC-3): AC-3 provides six separate discrete audio channels: left, right and center front, right and left surround and a low frequency woofer as a listener option. Dolby AC-3 is the first perceptual coding scheme designed specifically to code multi-channel digital audio. It divides sizes optimized with respect to the frequency selectivity of human hearing. This makes it possible to sharply filter coding noise and reduce data consumption while delivering dynamic theatre quality sound. Unlike Dolby surround, AC-3 is entirely discrete and features five full frequency (20-20KHz) channels and one low frequency effects i.e.: subwoofer (20-120Hz) channel. DVD players with AC-3 audio will still be compatible with Pro-Logic surround and two channel stereo systems.

Dolby Digital EX: Dolby Digital Surround EX adds a center rear surround channel to the 5.1-channel format, providing a new tool for delivering greater sonic reality and excitement to the audience. Since the format was introduced in May 1999, with the release of Star Wars Episode I: The Phantom Menace, audiences have thrilled to the added excitement in Toy Story 2; The Haunting; The World is Not Enough®; Austin Powers: The Spy Who Shagged Me; Fight Club; Pitch Black; The Bone Collector; The Messenger: The Joan of Arc Story; Bats; and Mission to Mars, among others. To date, more than 4,600 screens worldwide have been equipped for Dolby Digital Surround EX playback.

Dolby Pro-logic: The more advanced form of Dolby Surround that not only recovers the surround information from encoded program material, but also adds a center channel to keep dialogue and center effects firmly positioned on the television screen. Pro Logic permits a wider listening/viewing area, provides better channel separation, and gives more accurate sonic perspectives. There is also no digital connection necessary, just normal stereo (phono) outputs/inputs. The amplifier on the receiving end must be capable of decoding Dolby Pro Logic signals. The main difference between this and Dolby Digital is that the rear speakers are in mono (both output exactly the same) and there is no dedicated subwoofer channel.

DSP: Digital Signal Processor or Digital Sound Processor. These are audio effects added on-the-fly to sounds by a receiver or amplifier. They usually consist of echo and reverb effects labeled "jazz, theater, hall, etc."

DTS: Coherent Acoustics is a six-channel (5.1) audio system designed to deliver a higher-resolution multi-channel audio experience. DTS utilizes a perceptually transparent audio compression algorithm and a higher data rate (up to 1.5 mbps) to produce warm, natural, and rich sound from Compact Discs and film-based entertainment alike. DTS or Digital Theater Sound is another sound format available to consumers. As to which one is better, it's not my place to say here, but to experience a DTS track you need a DVD player AND receiver which can decode DTS audio tracks (usually denoted by the infamous DTS logo on the front of the hardware). Earlier discs that included a DTS (Dolby and DTS were oft given separate discs) were shy of extras due to the larger space the DTS track required on a disc. However, in the recent year we've seen some big advances in the technology and we’ve seen many discs released today that offer both audio formats.

DTS-ES: The new DTS-ES discrete 6.1 format employs a new, proprietary technology for the playback of discrete, 6.1-channel content from DVDs and CDs. The additional channel over 5.1 audio is a rear center channel. In addition to DTS-ES discrete 6.1 decoding, the new DTS-ES program includes the introduction of the DTS-ES Matrix 6.1 surround decoding format, which offers backward compatibility with existing ES matrix-encoded content, and DTS Neo:6, which is a matrix technology that derives up to 6.1-channel playback from conventional, stereo program material.

DVD: "Digital Versatile Disk." (Formerly Digital Video Disk.) Same size as a CD but stores seven times CD capacity on a single side. DVDs can also be double-sided or dual layer. Today most DVDs are used to display full-length commercial motion pictures, plus additional material such as outtakes, director's notes, movie trailers, etc.

DVD –Audio: This is a new audio format which offers multi-channel (5.1) surround sound music.

Dynamic range: The range between the loudest and softest sounds a sound format or system can reproduce.

Effects: Sound effects, i.e., the non-musical elements on a soundtrack other than dialogue.

Fiber optics: Thin glass filaments within a jacket or bundle that optically transmit images or signals in the form of light over distances, with extremely low high-bandwidth quality losses.

Gauge: Gauge is a unit used to measure wire thickness. The smaller the number, the thicker the wire. (i.e. 10 gauge wire is much thicker than 16 gauge wire). Typically, is it desireable to have the lowest gauge speaker wire possible. Around 12 gauge is ideal, above 18 gauge is not recommended for serious home theater applications.

4:3: Aspect ratio of the NTSC TV screen, with "4" unit width corresponding to "3" unit height, proportionally, regardless of the actual size of the screen.

16:9: Aspect ratio of widescreen DTV formats for all HDTV and some SDTV (Standard Definition) video. "16" unit width corresponds to "9" unit height, proportionally, regardless of the actual size of the screen.

HDTV: High-Definition Television. I'm sure that you have either heard or read the statement that HDTV is the biggest breakthrough in television since color. It truly is. If you have never seen HDTV, you are in for a treat. HDTV is simply incredible. It is the most life-like picture you can get with the sole exception of looking out a window. HDTV offers wider pictures with greater detail and the clarity of motion pictures. Compared to standard television (NTSC), the true HDTV image has twice the luminance definition - vertically and horizontally - and is twenty-five percent wider. Standard television aspect ratio is 4:3 - the HDTV aspect ratio is 16:9. The 16:9 ratio is much closer to the average widescreen image shown in movie theaters. However, the biggest difference between NTSC and HDTV is its clarity. True HDTV pictures are composed of 1080 active lines (1125 total) whereas current standard television pictures are composed of only 480 active lines (525 total). The lines that make up standard television pictures are clearly visible, but HDTV lines are not at all noticeable. The fine-grained HD picture contains five times more information than does the standard television picture and is accompanied by multi-channel, Dolby Digital audio.

Hertz: Units used to measure audio frequency.

Interconnects: Interconnects are a generic term for all of the audio and video cables that connect your system together.

Interlaced: A system of video scanning where odd- and even-numbered lines of a TV picture are transmitted consecutively as two separate interleaved fields. Interlace is a form of compression and has been used for decades in analog (NTSC) TV.

Letterbox: Image of a wide-screen picture on a standard 4:3 aspect ratio television screen, typically with black bars above and below. Used to maintain the original aspect ratio of the original source (usually a theatrical motion picture of 16X9 aspect ratio or wider).

LFE: Low Frequency Effects. These are the very deep booming bass sounds recorded into a Dolby Digital or DTS audio track. They are typically reproduced by the subwoofer in your home theater speaker system, however if a subwoofer is not present in the system, most receivers will attempt to reproduce these sounds through your main front speakers. Because it is not essential to the soundtrack, the LFE track is identified as the ".1" in a 5.1 digital audio recording. Soundtracks recorded as 5.0 Dolby Digital do not include a LFE track.

Lines of Horizontal Resolution: Lines of horizontal resolution are often confused with scan lines. The two are totally different things, be careful when shopping for equipment. Lines of horizontal resolution refers to visually resolvable vertical lines per picture height. In other words, it's measured by counting the number of vertical black and white lines that can be distinguished an area that is as wide as the picture is high. Lines of horizontal resolution applies both to television displays and to signal formats such as that produced by a DVD player. Since DVD has 720 horizontal pixels (on both NTSC and PAL discs), the horizontal resolution can be calculated by dividing 720 by 1.33 (for a 4:3 aspect ratio) to get 540 lines. On a 1.78 (16:9) display, you get 405 lines. In practice, most DVD players provide about 500 lines instead of 540 because of filtering and low-quality digital-to-analog converters. VHS has about 230 (172 widescreen) lines, broadcast TV has about 330 (248 widescreen), and laserdisc has about 425 (318 widescreen). Scan lines, on the other hand, measure resolution along the y axis. DVD produces 480 scan lines of active picture for NTSC and 576 for PAL. The NTSC standard has 525 total scan lines, but only 480 to 483 or so are visible. (The extra lines are black and are encoded with other information). Since all video formats (VHS, LD, broadcast, etc.) have the same number of scan lines, it's the horizontal resolution that makes the big difference in picture quality.

LPF: Low Pass Filter. A filter that passes frequencies below a certain point. Above that certain point it filters the frequencies out, relative to a certain rate measured in dBs per octave.

Luminance: Component of video data that includes technical "information" about its brightness.

MPEG 2: Compression standards for moving images and audio are set by the Motion Pictures Expert Group (MPEG), an international committee of industry experts. MPEG-2 is the basis for ATSC digital television transmission in the U.S.

NTSC: "National Television Systems Committee" and the name of the current analog transmission standard used in the U.S., which the committee created many decades ago. NTSC is also commonly used to refer to one type of television signal that can be recorded on various tape formats such as VHS.

The NTSC standard has a fixed vertical resolution of 525 horizontal lines stacked on top of each other, with varying amounts of "lines" making up the horizontal resolution, depending on the electronics and formats involved. There are 59.94 fields displayed per second. A field is a set of even lines, or odd lines. The odd and even fields are displayed sequentially, thus interlacing the full frame. One full frame, therefore, is made of two interlaced fields, and is displayed about every 1/30 of a second.

Ohm: Ohm is the unit used to measure the resistance presented by a loudspeaker when a it is introduced a signal by an amplifier. (The word Ohm comes from German physicist Georg Simon Ohm, 1787–1854). Conventional wisdom makes an 8 ohm loudspeaker load the most acceptable because it "protects" the amplifier from delivering too much current. A 4 ohm loudspeaker can encourage a marginally designed amplifier to deliver more current than it comfortably can. All speakers in your home theater system should have the same Ohm rating.

PAL: Phase Alternate Line. This is the 625 line color television system in use today in the United Kingdom and much of Europe.

Pan and Scan: When widescreen movies are being brought to home via medium of television broadcasting or home-video/DVD we are posed with the problem of fitting the picture to the standard 4:3 (1.33:1 ratio) television set. To beat this problem, studios use a technique referred to as "Pan and Scan" which actually crops the image so that the film will fill the 4:3 screen. This technique can in fact cause more than half of the original picture to be lost in the process.

PCM: Pulse Code Modulation. PCM is a digital scheme for transmitting analog data. The signals in PCM are binary; that is, there are only two possible states, represented by logic 1 (high) and logic 0 (low). This is true no matter how complex the analog waveform happens to be. Using PCM, it is possible to digitize all forms of analog data, including full-motion video, voices, music, etc.

Pink Noise: Pink noise is noise that has equal energy in each octave.

Pixel: A word derived from Picture Elements. This is the smallest unique point of a digital video image. In a Digital Video, a picture is divided up into thousand of Pixels, each specified by Luminance, Chrominance, and position information.

Progressive: Refers to "progressive scanning," as in DTV formats 480p or 720p. A system of video scanning whereby lines of a picture are transmitted consecutively (unlike interlaced), as on computer screens.

PWM: Pulse Width Modulation a method of representing analog signal levels in digital form by varying the width of the digital pulse. This technique is used for recording the analog Cue Tracks in DASH in the digital tape. First-generation DASH machines like the Sony PCM-3324 used bias recording.

Region coding: DVD discs around the globe are sold with a different regional coding depending on the area of the world. For example, American discs are region 1 whereas English and Japanese discs are region 2. This is a full list of the different regions Region 0: All areas of the world Region 1: United States and Canada Region 2: Japan, Europe, South Africa, Middle East Region 3: Southeast Asia, East Asia, Hong Kong Region 4: Australia, New Zealand, Pacific Islands, Central America, South America, Mexico, Caribbean Region 5: Former Soviet Union, Indian Subcontinent, Africa, North Korea, Mongolia Region 6: China Region 7: Unused Region 8: Special International Venues (e.g. airplanes, cruise ships, etc)

Resolution: Directly affects picture quality. The higher the resolution, the more picture detail there is. Many things affect resolution, including number of bits, pixel count, format, receiver quality, cameras, lenses and lighting used for live or taped programming, etc.

RGB: Abbreviation for red, green and blue signals, the primary colors of light -- and television.  RGB video transmission method. A video transmission method. Better than composite video and s-video, equal to component video. RGB video uses one 15 pin video cable (this is the same video cable and distribution method used in computer monitors) to distribute the video signal. Aside for PC's, RGB video is typically found on HDTV and DBS satellite systems.

Scan Lines: See Lines of Horizontal Resolution.

SCART: The large rectangular shaped objects on the rear of most European televisions are a form of television input that can operate in a variety of ways - a composite, RGB or S-Video signal can be passed through a SCART cable depending on what type of SCART socket you have on your television. With a suitable TV SCART also allows auto-switching when the connected device (e.g. DVD player) is activated.

Six-channel input: Many DVD players now have built in Dolby Digital decoders.To take advantage of these they need to be connected to a home cinema amplifier with a six channel input(one input for each surround sound channel)

SPDIF: Abbreviation for Sony/Philips Digital InterFace. Digital transmission format for the consumer marked. This self-clocking stereo signal can be transmitted optically or via a Cinch cable. The format is like the AES/EBU Standard but with other channel status and other electrical specifications.

Stereo: From the Greek word for solid; identifies sound recording and reproduction by more than one (mono) channel. In home music reproduction, "stereo" came to mean two channel sound. In the film industry, however, "stereo" came to mean at least four channels (left, center, right, and surround). This is why Dolby's film sound technology could be identified simply as Dolby Stereo for the film industry, and why a new term, Dolby Surround, was needed to identify multichannel home sound reproduction.

Subwoofer: A subwoofer is a (usually powered) speaker which produces very deep booming bass sounds. Subwoofers are responsible for reproducing the LFE track in a 5.1 Dolby Digital or DTS soundtrack. They are typically a cube shape with a large single woofer either pointing directly at the ground or directly at the listener. Usually, subwoofers are placed in the corner of the room. Ideally, a subwoofer should be placed where it is impossible to determine the direction of where the sound is coming from.

Supplemental Features/Extra Features/Bonus Features/Additional Materials: Bonus materials can range from feature length commentaries by people involved in the production, to documentaries on the special effects to just about anything that studios can generate to entertain dorks and geeks like us.

Surround sound: The reproduction of ambiance, atmospherics, and occasional special effects anywhere around the listener by means of multichannel sound reproduction.

S-Video: A video transmission method. Better than composite video, not as good as component video. S-video separates luminance (black and white information) and chrominance (color information) signals. An s-video cord slightly resembles a computer PS-2 cable.

THD: Total Harmonic Distortion. Harmonic Distortion is a means for measuring Nonlinear Distortion. Nonlinear Distortion is a form of signal processing error that creates signals at frequencies that are not necessarily present in the input. THD is determined by measuring the size of each of the new frequencies that are created by the source of the distortion. The new frequencies are called "harmonics" because they exist at frequencies that are integer multiples of the input signal.

TFT. LCD: The flat screen televisions and monitors we sell, are known as TFT's because these displays use TFT (Thin Film Transistor) technology, where each screen pixel is controlled by between 1 and 4 transistors, and the rows and columns of pixels are turned off and on by transistor grids. This improves on passive matrix technology by eliminating image ghosting (where a faint double-image appears) and quickening response speeds, delivering a smoother, more responsive and ultimately better quality picture.

UHF: Ultra High Frequency, 300 to 3000 Megahertz.

VHF: Very High Frequency, approximately 88 to 216 Megahertz.

White Noise: Noise that has equal energy at each frequency.

Widescreen: The pinnacle aspect of cinema viewing, generally referred to as 16:9 aspect ratio, widescreen ratios can actually differ between approximately 1.6:1 ratios and up. Widescreen enthusiasts will tell you that the original vision of the film is best

YPbPr: Another term for component video presented in a widescreen picture. There are a few side effects of using widescreen technology without the proper equipment? Black bars appear on standard televisions to compensate.