 Here are some brief, mostly non-technical explanations of some of the terms you may hear in an A/V store, see in an advertisement, or read about in an article covering home theater and HDTV. If you're still unsure of what a specific term means after reading our definition, please call or come by Bjorn's Audio Video. We'll be glad to take the time to give you a more enlightening explanation. (Sometimes it's easier to understand these concepts after a demonstration than it is to figure them out by reading about them. Besides, we like to do show and tell.)
Refers to a TV picture that is broadcast or shown on a screen using 1,080 lines of pixels that are scanned in an interlacing manner in which every other line is scanned/illuminated before the skipped lines are scanned/illuminated.
Refers to a TV picture that is broadcast or shown on a screen using 480 lines of pixels that are scanned in an interlacing manner in which every other line is scanned/illuminated before the skipped lines are scanned/illuminated.
Refers to a TV picture that is broadcast or shown on a screen using 480 lines of pixels that are scanned in a progressive manner in which each line is scanned one after the other.
1080p
Refers to a TV picture that is broadcast or shown on a screen using 1080 lines of pixels that are scanned in a progressive manner in which each line is scanned one after the other.
Refers to sound systems having five full-range channels (usually left front, center, right front, right rear, and left rear) plus a low-frequency effects channel. A 5.1-channel system will typically have six speakers total. Dolby Digital and DTS are both examples of 5.1-channel surround sound formats.
Refers to sound systems having six full-range channels (the same as in a 5.1-channel system but with the addition of a center back channel) plus a low-frequency effects channel. A 6.1-channel system will typically have seven or eight (if two are used for the center back as recommended by THX) speakers. Dolby Digital Surround EX and DTS-ES are both examples of 6.1-channel formats.
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Refers to sound systems with seven, discrete full-range channels plus a low-frequency effects channel. Some manufacturers of A/V receivers refer to their equipment as 7.1-channels when they include two discrete amplifiers for dual center back speakers. Although this is a good thing in terms of having available amplifier power, in reality no current surround encoding formats provide 7.1 discrete channels of information -- but, hey, there's always tomorrow! (Some companies refer to 7.1 when they mean 6.1 instead. The 2 speakers in the back are both playing the same information.)
Refers to a TV picture that is broadcast or shown on a screen using 720 lines of pixels that are scanned in a progressive manner in which each line is scanned one after the other.
Aspect Ratio
A television's aspect ratio is the relationship of the horizontal dimension (the width of the screen) to the vertical dimension (the height). It can be expressed as a ratio of whole numbers (4:3 or 16:9) or a ratio using fractional numbers for the width compared to the height of one unit (1.33:1 or 1.78:1). Images with wider aspect ratios tend to engage more of your peripheral vision and draw you deeper into the theatrical experience.
Bi-Wiring
A method of connecting an amplifier or receiver to a speaker in which separate pairs of wires are run between the amp and the woofer and the amp and the tweeter.
Bi-Amping
Using separate amplifiers and separate speaker wire for the tweeter and woofer of a loudspeaker.
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.
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Blu-ray Disc (BD)
A high-capacity, DVD-size format for high-definition video programs. Blue instead of red lasers are used to obtain high data density. Also see HD DVD.
CD-R
Recordable Compact Disc
CD-RW
Rewritable Compact Disc
Component Video
A signal that's recorded or transmitted in its separate components. 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 signal.
A device, either passive (as in a speaker) or active (as in a processor) that directs particular frequencies to particular drivers or speakers.
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.
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DVD-RW
A recordable DVD format similar to CD-RW in that it is re-recordable medium. Backed by Pioneer, Panasonic, Toshiba, and others.
DVD+R
A recordable DVD format similar to CD-R in that it is a write-once medium. Backed by Sony, Philips, Yamaha, HP, 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
DVD-RAM
A recordable DVD format similar to DVD-RW in that it is a re-writeable format. Unlike DVD-RW it is capable of being written to and erased over 100,000 times.
DVI (Digital Visual Interface)
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.
Digital Video Recorder (DVR)
A Digital Video Recorder is like a VCR, but with a hard drive and without the hassles of videotapes or timers.Think "tape-less" VCR and more. Digital Video Recorders record shows digitally and save them to a hard drive. All recorded programs are listed on your TV screen for playback in any order.
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™
Invented by Texas Instruments, the Digital Light Processing(TM) technology refers to a sophisticated combination of a light source, a projection lens, and a Digital Micromirror Device (known as the DMD chip) that contains over a million tiny, hinged mirrors used to reflect an image on to a screen. On this chip, each mirror corresponds to one pixel in the projected image.
Dolby Laboratories' method of encoding and decoding channels of audio for movies and music. Can be a single channel of sound all the way up to 7 channels (6.1).
Co-developed by Dolby and THX, Surround EX adds a center back channel to the five main channels of audio in Dolby Digital-sometimes referred to as 6.1 channels, the .1 being the LF (Low Frequency) effect channel sent to the subwoofer.
Dolby Laboratories' matrix method of encoding four tracks of audio information (left front, right front, center front, and rear) into two channels and then playing them back through a Dolby ProLogic decoder.
A generic term used to describe when a DTV tuner creates a lower resolution image (SDTV, for example) from a higher resolution one (HDTV, for example).
DSD
Direct stream digital. The trademark name used by Sony and Philips for their system of recreating audible frequencies which uses pulse-density modulation encoding, a technology to store audio signals on digital storage media which is used for the Super Audio CD (SACD).
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(competitor to Dolby Digital 5.1)
Digital Theater Systems name for a method of encoding channels of audio for movies and music. Can be a single channel of sound all the way up to 7 channels (6.1).
An extension of DTS to incorporate a center rear channel of audio information (6.1 total), similar to Dolby Digital EX and DTS-ES Discrete.
Short for Digital TV. When used to refer to a TV broadcast, DTV can mean any one of 18 different broadcast variations approved by the FCC. When used to refer to a television, DTV can mean any one of three different levels of television.
Short for Digital Versatile Disc. If you don't have a DVD player by now, you should.
Short for Enhanced Definition TV. This type of television must be able to display images at scanning rates higher than 480p but not as good as HDTV. It must also include a DTV tuner capable of receiving all 18 DTV broadcast formats.
An Enhanced Definition TV without an included DTV tuner.
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The moving video images you see on television are composed of lots of still images. In an interlace system, half of the lines (every other one) in the picture are active for 1/60th of a second. Then the system switches and activates the skipped lines for the next 1/60th of a second. Each of these "half" images is known as a field.
FireWire
See IEEE 1394.
An image on a TV screen using all of the lines. In an interlace system, two fields (1/60th of a second) combine to make one frame (one 1/30th of a second).
A type of television that projects an image onto a screen or wall in front of the projector.
HD DVD
A high-capacity disc format approved by the DVD Forum for carrying high-definition video programs. The sandwiched disc structure resembles that of ordinary DVDs. Outputs to 1080p
HDMI
High Definition Multimedia Interface. HDTV connection format using a DVI interface that transfers uncompressed digital video with HDCP copy protection and multichannel audio.
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Short for High Definition TV. This type of television must be able to display images at scanning rates of either 720p or 1080i. It must also be able to display these images in a 16:9 aspect ratio and include a DTV tuner capable of receiving all 18 DTV broadcast formats.
An HDTV without an included DTV tuner.
The process of creating an image on a screen by scanning or illuminating every other line in the image before going back and scanning or illuminating the skipped lines.
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,…
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.
A speaker that is mounted in the wall or ceiling of a home or office.
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A television that uses an Liquid Crystal Display panel to create an image. Some examples are LCD flat panel TVs, LCD-based rear projection TVs, and LCD-based front projection TVs.
LCOS
Liquid Crystal on Silicon is a "micro-projection" or "micro-display" technology typically applied in projection televisions. In LCOS, liquid crystals are applied directly to the surface of a silicon chip coated with an aluminized layer, with some type of passivation layer, which is highly reflective.
LED (light-emitting diode)
A semiconductor device used as an indicator light on many components. lenticular: In video, anything containing many small lenses; commonly used to describe video projection screens optimized to produce high picture brightness in certain viewing directions. This technology is used in some rear projection and flat panel displays.
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.
Usually an outboard device, although sometimes built in to a high-scan capable TV, that adds additional scanning lines to images composed of fewer scanning lines (like NTSC images).
Macro
When referring to remote controls or home automation, a "macro" is a sequence of commands that are sent to your system ("receiver power on", "select DVD input", "select Dolby Digital", "DVD power on", "DVD play", "dim the room lights", etc.) as the result of touching one button.
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Midrange
The range of frequencies that lie between midbass and the high frequencies.
MP3
The name of the file extension and also the name of the type of file for MPEG, audio layer 3. Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3 uses perceptual audio coding and psychoacoustic compression to remove all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal. The stuff the human ear doesn't hear anyway).
Because MP3 files are small, they can easily be transferred across the Internet.
A term that refers to having the same sound or pictures in more than one room of your home.
A term that refers to the ability to have different sound or pictures in more than one room of your home at the same time.
NTSC
National Television Standards Committee. Government-directed committee that established the U.S. color TV standard in 1953. Also known, sarcastically, as Never Twice the Same Color or Never The Same Color due to the inherent difficulty in achieving proper color calibration.
Networking
The linking of a number of devices, such as computers, workstations, printers, and AV gear into a network (system) for the purpose of sharing resources.
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Optical Digital Cable
Fiber optic cable that transfers digital audio signals as light pulses.
Plasma
Flat-panel display technology that ignites small pockets of gas to light phosphors.
The process of creating an image on a screen by scanning or illuminating each line in the image one after the other.
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.
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.
A type of television in which the image is projected onto a screen from behind.
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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.
Short for Standard Definition TV. This type of television must be capable of displaying a DTV image using 480 lines scanned progressively. It must also include a DTV tuner capable of receiving all 18 DTV broadcast formats.
An SDTV without the included DTV tuner.
A method of wiring a home for audio, video, telephone, and computer using a centrally located, often modular panel.
A speaker specifically designed to reproduce the lowest frequencies in music and movies.
THX
THX is the trade name of Lucasfilm Limited's high-fidelity sound reproduction system for theatrical movie theaters, screening rooms, home theaters, and car audio systems. THX was developed by George Lucas's company in 1983 to ensure that the soundtrack for the third Star Wars film would be accurately reproduced in the best venues.The THX system is not a recording technology, and it does not specify a sound recording format; all digital and all analog sound formats can be "shown in THX." THX is mainly a quality assurance system.
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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 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.
A part of a full-range loudspeaker that's designed to reproduce the higher frequencies.
Typically used to describe the process by which a DTV tuner or HDTV creates additional scanning lines for an image that starts with fewer scanning lines. This is sometimes referred to as line doubling.
A part of a full-range loudspeaker that's designed to reproduce the lower frequencies.
Y/Pb/Pr
See component video.
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