Audio and Video Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

2.0

(Pronounced 'two-point-oh'). A stereo soundtrack composed of the following discrete audio channels:

• Front Left
• Front Right

5.1

(Pronounced 'five-point-one'). A soundtrack composed of the following discrete audio channels:

• Front Left
• Front Center
• Front Right
• Rear Left
• Rear Right
• Low Frequency Effects (generally sent to the Subwoofer).

6.1

(Pronounced 'six-point-one'). A soundtrack composed of the following discrete audio channels:

• Front Left
• Front Center
• Front Right
• Left
• Right
• Rear Center
• Low Frequency Effects (generally sent to the Subwoofer).

7.1

(Pronounced 'seven-point-one'). A soundtrack composed of the following discrete audio channels:

• Front Left
• Front Center
• Front Right
• Left
• Right
• Rear Left
• Rear Right
• Low Frequency Effects (generally sent to the Subwoofer).

A

AAC - Advanced Audio Coding

An audio codec used increasingly for downloaded music files, streaming-media, and satellite-radio applications. AAC is similar to MP3, but offers a number of advantages designed to improve audio quality. These include higher-efficiency compression, more channels, and much better handling of audio frequencies above 16 kHz. Apple's popular iTunes music service employs the AAC format.

AC-3

(Adaptive Transform Coder 3) See Dolby Digital.

Acoustic Suspension Speaker

A speaker system housed in a sealed box, non ported. The air in the enclosure acts as a spring that shapes the response of the driver/box system. Acoustic suspension designs have lower sensitivity than ported designs and need additional amplifier power to achieve the same sound pressure level as a ported speaker. Acoustic suspension designs are able to play lower in the frequency spectrum at the same volume, and provide tighter and better-defined sound. Not all sealed speakers are acoustic suspension designs.

Active Scan Lines

The scan lines in a video frame that carry picture information rather than data for closed captioning or synchronization.

Active Speaker

A speaker that has it's own power supply and amplifier. An active speaker will have its own volume control.

AD or A/D

An abbreviation of Analog to Digital conversion, or Analog to Digital Converter. See also D/A.

Ambient

An audio quality generally associated with surround sound when the rear channels reflect sounds from the front by reproducing them several microseconds out of phase. This is heard when characters in a film go into a large room and their voices echo. Ambient can also mean any atmospheric or mood setting characteristics on a soundtrack. Music or the sound of rain enveloping the audience in a good surround is said to ambient.

Amp

Abbreviation for either an ampere or an amplifier.

Ampere

A measure of electrical current, electricity measured by volume is the total amperage. Also referred to as an 'amp'.

Amplifier

An audio component that amplifies an audio signal, the amplified signal is intended for speakers to reproduce the sound at high volumes. Also referred to as an 'amp'.

Analog

A system of representing information continuously rather than incrementally. The converse of analog is digital, which is a more sophisticated means of electronically storing and transmitting information.

Anamorphic

A video encoding technique the stretches a 16:9 image vertically to make it fit the 4:3 format natively supported by DVD's. The DVD player either expands then squeezes the image vertically back to the 16:9 format for display on a widescreen display, or adds black bars to the top and bottom of the image (known as letterboxing) to fit a 4:3 display. Images that are wider than 16:9, such as 1.85:1 or 2.39:1, cannot be supported natively on a DVD and must still be letterboxed into the final 16:9 frame with varying amounts of black bars. Anamorphic encoding is generally referred to as 'anamorphic widescreen', 'enhanced for 16x9', or 'enhanced for widescreen televisions' on DVD packaging.

Anechoic

Literally 'no echo'. An anechoic chamber is a room specially designed to produce no echo and used by speaker manufacturers as an audio lab for testing speakers.

Antenna

A method of receiving radio frequency signals (RF) and channeling it through a signal path.

Aspect Ratio

Refers to the shape of a TV screen. The traditional TV screen that is nearly square has a ratio of 4:3 (4 units wide, 3 units high). The widescreen format has a ratio of 16:9 (16 units wide, 9 units high), which approximates the proportions of actual movie theater screens.

ATSC

Established in 1982, the Advanced Television Systems Committee is the group that developed the ATSC digital television standard for the United States, also adopted by Canada, Mexico, Taiwan, and South Korea, and being considered by other countries. For more information see www.atsc.org.

Audio

Audio is sound.

Audio Frequency

The audible range of sound to the human ear which is about 20 Hz to 20 KHz.

Audio Visual

A/V refers to anything electronically pertaining to sound and vision. Sometimes refers specifically to jacks or plugs used to connect sound and video from electronic sources.

Audiophile

A person who appreciates fine audio. Can also refer to a particular mindset that perpetually believes there is a "perfect sound" to be experienced by spending just a little bit more money on audio equipment. Audiophile is generally a broad term that can refer to simple appreciation of fine sound to someone who believes in all the subjective rhetoric of high-end audio component reviews.

AV Receiver

An Audio Visual receiver is an integrated amplifier, preamplifier, tuner and processor. Although AV Receivers generally perform no video functions for Home Theater, video is wired through them for convenient switching between audio/video devices.

B

Backlit

The method used to light LCD and LED TV's. A light source such as LED' or CCFL tubes pass light from the back of the TV panel through a semi-translucent screen to the viewer.

Backward Compatibility

The ability of newer technology to work with older technology without any modification.

Band

A group of musicians who collaborate with instruments to produce music.

Bandpass

An audio filter that permits only a certain band of audio to pass by filtering all signals higher or lower than the bandpass. Bandpass filters are used in speaker system's crossover circuitry to permit only frequencies consistent with the speaker's accepted range.

Bandwidth

• A frequency range. In audio, a wide bandwidth might be the range of human hearing; 20 Hz to 20 KHz where a narrow bandwidth might be around a precise signal 199-201Hz.
• The maximum data a circuit can transmit over per second. e.g. A HDMI cable has a maximum bandwidth of 9.9 Gbps (gigabits per second).

Bass

Low pitched sounds represented by frequencies of 200Hz and below.

Bass Reflex

Speakers that use a ported box or a passive radiator. The port is used to extend bass response of the speaker. Bass reflex speakers do not necessarily sound inferior to an acoustic suspension speaker, but when poorly designed can produce an unpleasant booming 'one-note' bass.

Betamax

(Also Beta) This is Sony's original video recording standard released to the public in 1975. Beta was the loser to VHS in the video cassette format war of the early 1980's despite being largely considered technically superior.

Belling Lee Connector

See IEC 169-2.

Bi-Amping

The use of two amplifiers to power a single speaker system, one amp may power the tweeter while another powers the midrange. Only certain speaker designs permit bi-amping. Any speaker with a built in powered subwoofer is considered bi-amped.

Bipolar Speakers

A speaker design with separate facing cones within a single enclosure that operate out of phase. For Dolby Pro Logic surround systems this was preferred for its ability to produce ambient rear channel sounds. The source of the sound cannot be easily pinpointed by the listening audience when bipolar speakers are positioned properly which is the desired effect for Pro Logic Surround.

Bit

A binary value represented by a single digit; 0 or 1 for off or on respectively.

Bitrate

A measure of binary bits within a certain period of time, usually bits per second. Theoretically the higher the bitrate, the higher the quality of the audio or video. Bitrates vary widely between the different formats:

• CD - 16 bits per sample x 44,100 samples per second x 2 stereo channels = 1.41 Mbps
• SACD - 2.862 Mbps
• DVD-Audio - 9.6 Mbps
• Dolby TrueHD - 18.64 Mbps
• DTS HD - 24.5 Mbps
• Blu-ray - 40.0 Mbps

Bitstream

A row of binary bits intended to be processed one after another. A playback device such as a DVD player that reads digital multi channel audio information such as Dolby Digital or DTS reads the information as a bitstream to be processed sequentially.

Bi-Wiring

A wiring method where a single amplifier splits its speaker wire to two separate points on the speaker system's crossover, i.e. One wire comes out of the amp and is split separately into the tweeter, midrange and/or woofer depending on the speaker system.

Black Level

The level of brightness at the darkest (black) part of a visual image on a display. Video displays usually need to be configured to display a true black.

Blu-ray

Blu-ray Disc (BD) is a next-generation optical disc format meant for storage of 25 gigabytes (GB) of high-definition video or data. Jointly developed by a group of consumer electronics and PC companies called the Blu-ray Disc Association (BDA). The format was the victor in the format war with HD DVD. Blu-ray supports both the Dolby TrueHD and DTS HD audio formats, but Dolby TrueHD is mandatory on all discs with video content.

BNC

An audio or video connector used in place of RCA connectors on professional equipment. It is named after its 'Bayonet' locking mechanism and its two inventors 'Neill' and 'Concelman'.

Boomy

A characteristic of over-represented mid-bass in a Home Theater system. Boomy bass is opposite of full, dynamic, tight or other adjectives that describe a Home Theater system's ability to reproduce many different tones of bass from very low to medium low frequencies in quick succession.

Bridging

A setting in a two channel amplifier that switches it to more powerful mono or single channel amplifier.

Brightness

A measure of how much light is emitted by a display or a projector. Measured in candelas per square metre (cd/m²). Also known as luminance.

Burn In

A potential hazard with CRT & plasma displays. Burn in is caused when a high contrast stationary image is left on the screen too long and permanently alters the display. The burnt in image appears as a ghost image on the screen. LCD and DLP displays are immune to burn in effects.

C

Calibration

The process of adjusting sound and video equipment to optimize their output. Calibration DVD's can be purchased to provide tools to make the calibration process easier.

Carpet Spike

Small sharp feet used to keep speakers securely placed on a carpet.

CCFL

Cold Cathode Fluorescent Lamps - the light source found in LCD TV's

CD

(Compact Disc) A popular digital storage medium that took hold in the early 80s. CD's that exactly meed the technical standard laid down by Philips are also known as Redbook CD's.

CD-R

(Compact Disc-Recordable) A CD containing data that can be read by a CD ROM (Read Only Memory) drive. CR-R's can have data burned into the disc material just once using a CD ROM Burner (a type of CD-ROM drive).

CD-RW

(Compact Disc-Rewritable) A CD that can have data written to it and then overwritten later with different data. A CD-RW will be of a different composition than the CD-R but same equipment can burn information into both.

Channel

Separate signal paths in an amplifier. A two channel amplifier (i.e. 2.0) has two separate outputs, e.g. Left Speaker and Right Speaker.

Chrominance

The color information of a video signal, including hue and saturation, but not brightness (also known asluminance).

Class A Amplifier

A design of amplifier where the outputs conduct current all the time. Known for having low distortion and high quality, these amplifiers are not very efficient and use large amounts of power.

Class B Amplifier

A design of amplifier that has high efficiency, but also a high degree of distortion. Class B designs are usually limited to use in devices where low power consumption is critical, e.g. battery powered equipment such as 2-way radio.

Class AB Amplifier

A combination of the technologies used in Class A & Class B amplifiers. These are the most common mainstream, mass produced amplifiers. Class AB amplifiers tend to be cheaper but aren't necessarily poor quality. Unlike Class A, the Class AB amplifier does not conduct current full time, so it draws less power and generates less heat than Class A.

Clipping

Occurs when the peak of an analog signal is cut off at the top. This occurs when an amplifier is driving a signal to it's absolute maximum and can no longer produce the power required to drive that signal through the peak. The signal will clip producing audible distortion.

Coaxial Cable

Also known as Coax. A thick round type of cable well insulated by a cylindrical braid or shell surrounding a copper conductor running through the center. The construction consists of a round conducting wire, surrounded by an insulating spacer, surrounded by a cylindrical conducting sheath, and surrounded by a final insulating layer. RG-6/U or RG-6/UQ (quad shield) coaxial cable is generally used for aerial connections, cable television, satellite television and cable modems.

Cold Cathode Fluorescent Lamps

See CCFL

Colour Space

A model for representing color in terms of measurable values, such as the amount each of red, green, and blue, or hue, value, and chrominance in an image. RGB and CMYK color spaces correspond to color devices - displays and printers - respectively.

Colour Temperature

The hue of white light from a display. Measured in degrees Kelvin, the lower the colour temperature of the display the more white light will appear redish, while displays with a higher colour temperatures make white light appear bluish. PAL and NTSC TV's are calibrated to a standard of 6500K (though some TV's vary widely from the standard). Computer monitors and some plasma & LCD displays can be set to various colour temperatures, though 6500K (also known as 'sRGB') is recommended, as this is what digital cameras, web graphics, and DVD's, etc. are normally designed for.

Comb Filter

Named for the shape of the sine wave that looks like the teeth of a comb. The comb filter is used to separate luminance and color information from an analogue video signal. This step is helpful for converting to digital for further processing and/or transmission through a Home Theater system. Comb filtering is irrelevant when the video source is digital (e.g. DVI-D)or transmitted from a video source that has already separated luminance from color (e.g. an S-Video cable). Also available as a digital comb filter.

Component Video

An analog video signal format, that provides better picture quality than composite or S-Video by splitting the signal into brightness or contrast values (known as the 'Y' signal), chrominance (known as the 'C' signal) which is the red and blue information. Green values are calculated by a deductive process from reading all three signals. Component video comes in two forms known as YPrPb and YCrCb. There is also a digital form of YCrCb found on professional level equipment. Component video signals are carried via component video cables.

Component Video Connector

A method of transmitting an analog video signal between video components. The video signal is sent via three separate cables containing luminance, synch and color information. Component video is superior to S-Video but inferior to DVI and HDMI connections. For more information see here.

Composite Video

The format of an analog television (picture only) signal before it is combined with a sound signal. The standard connection for composite video is via a yellow RCA connector. For more information see TV Connectors.

Compression Artifacts

Artifacts are jagged lines, blocks or graininess that appear in a video image that has been compressed to take up less storage and bandwidth. The more you compress an image the more compression artifacts will appear.

Contrast

Also called picture control or white level. Contrast represents the total light output from the picture. Contrast is the most important adjustment to make when you bring your new television set home. Manufacturers usually keep the contrast turned up all the way as a factory default setting, this helps get their model noticed by potential buyers.

Contrast Ratio

The difference or ratio between the blackest of blacks and the brightest whites. A higher contrast ratio means the TV is better able to differentiate fine details in colour. A contrast ratio of 800:1 is OK, 1500:1 is better and 2000:1 or higher is very good.

Convergence

Proper alignment of three video color beams in a CRT or independent picture tubes in rear projection television. Generally an issue reserved for CRT rear projection television sets where convergence can become a problem. Convergence problems in a picture are apparent when images have halos or bleed colors from around the edges. Setting convergence of separate red, green and blue color sources is an imprecise art and tends to involve compromise of good convergence in one area of the picture for slight problems in another.

Crossover

An electronic circuit that separates signals by frequency. Common use of a crossover is in a speaker that use crossovers to prevent low frequencies from reaching tweeters and high frequencies from reaching the woofers by filtering out the undesirable frequencies with band pass filters.

Crossover Point

A crossover point is the frequency that a crossover begins to filter. For example, a switch in a receiver sets a surround speaker from large to small. The receiver will not send low frequencies to the small speaker. The crossover point is the frequency where the filtering begins which could be 200Hz, so nothing below the 200Hz crossover point will reach the speaker set to small in the receiver's bass management setting.

CRT

(Cathode Ray Tube) Picture tube in a TV set or computer monitor. CRT rear projection TV sets have three CRTs one for each primary video color, red, green and blue.

Current

The flow of electricity through a circuit, current is measured in amps. Sometimes components are said to be high current, which means the circuit should be able to tolerate a high quantity of amperage or total quantity of electricity. This is a good attribute of electronic devices especially a Home Theater amplifier where peaks in the soundtrack vary the current requirements of the circuitry very quickly. Even the highest current circuitry in an audio component is limited to the capacity of the power supply to provide that current. This is why a heavy-duty power supply is instrumental in a good amplifier.

D

DA or D/A

(Digital to Analog) Processing of digital audio or video signals analog which should be the final stage of processing before being presented through playback. See also A/D .

DAC

(Digital to Analog Converter) A type of processor found in Home Theater equipment the converts digital audio signals such as those read off a CD or DVD to analog that we can hear. Receivers and DVD players might have DACs. These chips are an important part of the signal path of your Home Theater equipment, there is a wide variety in quality of DACs. Burr-Brown and Wolfson are high quality name brand DACs.

DAT

(Digital Audio Tape) A cassette tape recorder that records digital rather than analog signals magnetically like a conventional tape deck. The technology predates CD-RW but effectively performs the same function. Although the technology has fallen from consumer favor it's far from obsolete because it's a digital recording technology. As long as you can get blank tapes a DAT in your system will always have a purpose.

Datastream

See Bitstream.

Db

See Decibel.

DC

(Direct Current) Electrical energy that flows in one direction.

Decibel

(dB) One tenth of a Bel. Named for Alexander Graham Bell. A unit of sound pressure or loudness as perceived by the human ear. 1 dB is considered the smallest difference between two volume levels the human ear can hear.

Definition

In both audio and video the amount of definition is the amount of information being displayed at once. High definition images can be measured in resolution either as pixels or scan lines, differences are obvious to the viewer. In sound definition is generally measured by Pulse Code Modulation (PCM), number of bits per cycle and number of cycles per second. In sound the definition will determine how many different sounds can be heard at the same time. Audio definition is less obvious than video, so technology that delivers higher definition sound are slower to catch on than higher resolution video.

Delay

The time between a sounds production and delivery to the listener. Sound always travels at a static rate, the delay between sound coming from speakers in a Home Theater system and that sounds arrival to the ear is instrumental in the audience's perception.

Digital

Literally "Of Numbers". Information expressed in binary. Binary information, thanks to semiconductor technology, is easily transmitted and processed electronically without degradation of the input value. Since we see and hear in analog, the science behind Home Theater technologies is a perpetual dance between digital convenience and analog purity and realism.

Digital Comb Filter

Named for the shape of the Sine wave that looks like the teeth of a comb. The comb filter is used to separate luminance and color information from an analogue video signal. This step is helpful for converting to digital for further processing and/or transmission through a Home Theater system. Comb filtering is irrelevant when the video source is digital (e.g. DVI-D) or transmitted from a video source that has already separated luminance from color (e.g. an S-Video cable). Unlike an analog comb filter a digital comb filter uses a microprocessor that precisely separates the video signal.

Digital Light Processing

Developed by Texas Instruments in 1996, DLP generates images by passing white light through a colour wheel to produce the coloured light, which is then reflecting off the surface of a digital micromirror device (DMD) containing hundreds of thousands of tiny mirrors, and through a lens onto the screen. Higher resolution projectors have more mirrors in their DMD's, reflecting a greater amount of light for brighter images. For more information see here.

Digital Output

A digital output is generally found on a CD or DVD player and usually audio (S/PDIF is a digital audio output format) but today there are video outputs too. Conventional wisdom states using digital outputs when available is superior because it retains the purity of the signal read from the media. Generally you only want digital to audio conversion to take place as close in the signal path to the point the information reaches your eyes and ears (i.e. before being amplified or displayed on the TV). This is why digital video outputs have been a breakthrough for Home Theater.

Digital Video Disc

See DVD.

DLP

See Digital Light Processing.

Dolby AC-3

See Dolby Digital.

Dolby Laboratories

Founded by Ray Dolby in 1965, Dolby Laboratories became famous for tape noise reduction technologies during the 1970's and 1980's. It now produces a number of technologies used in film, audio, and DVD production/playback.

Dolby Digital

Originally called AC-3 (Adaptive Transform Coder 3)and also known as Dolby AC3, this audio encoding format delivers 5.1 discrete channels of surround sound with a bitrates generally ranging from 384 kbit/s to 448 kbit/s (although capable of 640 kbit/s). This is the standard audio format used in DVD & DVD-Audio.

Dolby Digital EX

An audio technology found in some home theatre amplifiers that can take 5.1 channel Dolby Digital audio and create 6.1 or 7.1 channel audio. The format is not considered true 6.1 or 7.1 channel audio because it unlike the competing DTS-ES technology it lacks the capability to support a discrete 6th channel. For more information see here.

Dolby Digital Live

Similar to DTS Interactive, Dolby Digital Live is a real-time encoding technique that converts common audio formats, including 3D sound from games, into a Dolby Digital signal that can be sent out the S/PDIF port of a PC sound card. Dolby Digital Live is used when dealing with sound sources that are not in Dolby Digital or DTS but surround sound is required from a home theater audio setup. The common examples of this are gaming and WMV-HD videos (which uses Microsoft's proprietary 5.1 channel audio codec) or DirectSound3D/EAX 3D sounds from games.

Dolby Digital Plus

Similar to Dolby Digital, but delivers 7.1 discrete channels of surround sound (with support up to 13.1 channels) and an increased bitrate up to 6.144 Mbit/s. This is the audio format used for HD DVD, and is an optional audio format for the Blu-ray disc.

Dolby Digital Surround EX

Whereas Dolby's Pro-Logic IIx format creates 6.1 and 7.1 channel output from stereo 2 channel (2.0). Dolby formats, the Digital Surround EX codec adds a sixth and sometimes seventh channel to standard (non-EX) 5.1 channel Dolby Digital soundtracks.

Dolby Pro-Logic

Introduced in 1987, this is an audio technology found in some home theatre amplifiers that can take stereo (2.0) audio and create four discrete channels. The result (particularly with music) was generally poor compared to modern multi-channel audio such as Dolby Digital or DTS. The channels produced by Dolby Pro-Logic are:

• Front Left
• Front Center
• Front Right
• Mono surround channel that is usually split between two rear speakers.

The surround channel is 'band-limited' to 7 kHz, reducing the treble frequencies. For more information see here.

Dolby Pro-Logic II

Also known as DPL II, this is an audio technology found in some home theatre amplifiers that can take stereo (2.0) audio and create five channel (5.0) audio. Dolby Pro-Logic II is a modern update of the often disappointing Dolby Pro-Logic technology. The channels produced by Dolby Pro-Logic II are:

• Front Left
• Front Center
• Front Right
• Rear Left
• Rear Right

Unlike Dolby Pro-Logic, Dolby Pro-Logic II produces two discrete full-range rear channels spanning 20Hz to 20 kHz. For more information see here.

Dolby Pro-Logic IIx

An audio technology found in some home theatre amplifiers that can take stereo (2.0) or 5.1 audio and create 6.1 or 7.1 channel audio. A competing technology to DTS NEO:6. For more information see here.

Dolby Surround

Introduced in 1982, this was the consumer implementation of the Dolby Stereo technology used in cinemas. The Dolby Surround technology is found in some stereo VCR's and TV's and can take stereo (2.0) audio and create three discrete channels. Dolby Surround was superseded by Dolby Pro-Logic in 1987. The channels produced by Dolby Surround are:

• Front Left
• Front Right
• Rear

Dolby TrueHD

This is the latest audio format from Dolby Laboratories and provides a lossless coding technology using a 18 Mbps bitrate, and 7.1 channels (it can support more than 8 channels) of 24-bit/96 kHz audio. This is the audio format used for HD DVD, and is an optional audio format for the Blu-ray disc. Dolby TrueHD is backwardly compatible with Dolby Digital equipment.

Dot Pitch

The distance (measured in millimetres) between phosphor lines of the same colour (i.e. the height of the triad, plus the distance between triads) in a CRT TV or computer monitor. The dot pitch is a measure of the sharpness of the picture, the lower dot pitch the better. Dot pitch is a bigger issue for CRT computer monitors than CRT TV's, due to the shorter viewing distance making the dot pitch more apparent. Some older CRT monitors have a .32 dot pitch, but today virtually all CRT monitors are .28 or better.

Downscaling

Reducing the number of pixels in a signal so that it matches the maximum resolution a display can support. An example would be the downscaling of a 1080i signal by a 720p TV. Downscaling is the opposite of upscaling.

Driver

An individual speaker cone within a speaker box. A speaker box (e.g. a left speaker or right speaker) may contain several drivers of different types - such as atweeter, midrange, or woofers.

DRM

(Digital Rights Management)The use of any of a variety of technologies to handle the description, valuation, trading and monitoring of the rights held over a digital work. A subset of DRM is copy protection, preventing the unauthorised copying of digital content. Examples include Macrovision and HDCP.

DTS

(Digital Theatre System) An audio format used on DVD's and in some cinemas. DTS bitrates range from 768 kbit/s to 1.5 Mbit/s (1536 kbit/s, the maximum bitrate a S/PDIF connection can transfer). DTS is found on some DVD's but is far less common than Dolby Digital as its higher bitrate leaves less space on the DVD for video content compared to Dolby Digital. The higher bitrate in DTS doesn't necessarily equate to better audio than Dolby Digital, as some of the frequencies encoded by DTS are inaudible to the human ear. For more information see here.

DTS 96/24

A Digital Theatre System 5.1 channel audio format that supports 24-bit, 96 kHz audio on DVD's and DVD-Audio discs. Prior to the invention of DTS 96/24, it was only possible to deliver a maximum of two channels of 24-bit, 96 kHz audio on a DVD.

DTS-ES

A Digital Theatre System 6.1 channel audio format that comes in two variants:

• DTS-ES 5.1 - The most common of the two variants, where the Rear Center channel is extracted from the Rear Left and Rear Right channels using flags hidden in the digital soundtrack.
• DTS-ES 6.1 - The Rear Center channel is encoded as a discrete channel.

DTS-ES is backwardly compatible with DTS equipment.

DTS HD

(Digital Theatre System High Definition) Previously known as DTS++, this audio format can support a virtually unlimited number of surround sound channels, and can support bit rates from 768 kbit/s to lossless. Although technically superior to the competing Dolby TrueHD format, DTS HD is only an optional audio format for Blu-ray and HD-DVD discs.

DTS Interactive

Similar to Dolby Digital Live, DTS Interactive converts PC audio to a 5.1 channel DTS signal that can be processed by any DTS enabled system via a single digital cable connection. The data transfer format is 48 KHz at 1.5 mb/sec. DTS Interactive is most commonly found on some PlayStation2 games.

DTS NEO:6

An audio technology found in some home theatre amplifiers that can take stereo (2.0) content and create 5.1 or 6.1 channel audio. A competing technology to Dolby Pro-Logic IIx.

Digital Rights Management

See DRM.

Dual Link

See DVI.

DVB

DVB or Digital Video Broadcasting is a set of internationally accepted, open standards for digital television published by a Joint Technical Committee of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU).

Digital Visual Interface

See DVI.

Digital Video Recorder

(DVR) See Personal Video Recorder (PVR).

DVD

(Digital Video Disc) DVD's generally use Dolby Digital or DTS (or both) for their audio format.

DVD-Audio

Also known as DVD-A, DVD-Audio is based on the MLP lossless encoding technology. DVD-Audio discs contain either 5.1 channels of 24-bit/96 kHz audio or two (2.0) channels of 24-bit/192 kHz audio and are competing technology to SACD's. DVD-Audio discs often have extra unreleased tracks, photo slide shows of the artist performing, song lyrics, music videos, and interviews. While technically superior to CD's (CD's have 1/7th the data capacity and a much lower and a much lower 16-bit/41.1 kHz bitrate), DVD-Audio never gained much consumer acceptance, and titles are limited.

DVI

Digital Visual Interface - a connector that carries analog or digital video. Capable of carrying high-definition signals such as 720p, 1080i and 1080p. For more information see TV Connectors or a detailed explanation of DVI here.

E

EDTV

(Enhanced Definition Television) EDTV is a standard of digital television that presents 480 progressive scan lines or 480p as the standard is called. Although 480p is a noticeable improvement over the traditional 480i, it is generally not regarded as HDTV

Efficiency

In audio electronics it's the measure by which a device is able to convert electrical energy into mechanical force or vice versa. Efficiency can be rated by the input vs. output. The greater the efficiency rating of a loudspeaker the more decibels it can put out with a given amount of power put in.

Efficiency Rating

(Also see Sensitivity) A specification associated with a loudspeaker that determines how loud it will perform for a given input of power. The higher the efficiency the louder it plays, the lower the efficiency the more power it requires from the amplifier for volume.

EICTA

The European Information, Communications and Consumer Electronics Technology Industry Associations. For more information see here.

Electrostatic Speaker

A type of speaker that employs electromagnetically charged metallic panels that vibrate air between them to produce sound. The same principal is used for Ribbon speaker, both types of speakers can be considered planar magnetic. Planar speakers are flat and known for producing detailed sound.

EMF

Can be either Electromotive Force, voltage. Or Electromagnetic Field, which is the magnetic energy surrounding electronic circuits.

Enhanced 16:9

This is an aspect ratio found on DVDs that show a movie in the original aspect ration from the theater. Enhanced or widescreen films are superior and necessary for true Home Theater because they show the whole movie and not a cropped pan and scan version, without it a movie is just a TV show. Enhanced format DVD force the aspect ratio onto conventional sized televisions by cropping the bottom and top portions of the screen, some call them black bars. On larger televisions (''32 or greater) this should only take a few moments to get accustomed to. If you've never watched a movie this way, start.

EQ

Equalizer or equalization. A component or a feature built into a receiver that allows you to control the volume of isolated bands of the full frequency of audio. Your goal with an equalizer is to create as flat a frequency response as possible. An EQ can also be used to compensate for taste in sound or weakness in a system by pumping up a particular frequency or turning down another.

F

Feedback

Anytime a portion of the output of a device returns as input to the device. Feedback becomes a problem when the returning input is out of phase with the output.

Fiber Optic

A type of cable that transmits digital information as pulses of light. TOSLINK cables are fiber optic cable for use with Home Theater. Its large data capacity and immunity from the electrical interference generated by other cables make it useful choice where signal quality is paramount.

FireWire

(Also called IEEE 1394, or iLink) Similar in use to a USB connection This high speed digital connection technology is now used as connector for Home Theater applications. Many newer TV's have a FireWire port used for video sources such as a camcorder. For more information see here.

Flat Panel

A screen with a flat glass display and minimal depth. Examples include Plasma and LCD TV's, and exclude CRT, Rear Projection and Projector displays.

Flat Response

The desirable state attained in an audio system when all frequencies are capable of being played back at the same volume. Flat refers to how a wide band of audible frequencies would appear on a graph where volume of each frequency is being charted.

Format War

A battle in the marketplace between two competing formats. Examples include Beta vs. VHS and Blu-Ray vs. HD DVD. Format wars usually start when the creators of competing technologies can't agree on a compromise technology and decide to battle it out in the marketplace. They are generally a bad thing for consumers as they delay adoption of new technologies while consumers wait to see which technology emerges as victorious. Also, the ultimate victor may not even be the better technology, e.g. Beta vs. VHS, where Beta was widely considered to be technically superior but lost out to VHS and its superior array of content.

Frequency

Cycles per second measured as Hertz (Hz). Since sound travels in waves it can be measured in cycles per second or frequency. The audible frequency range is said to be approx. 20 Hz to 20 KHz.

Full-Range

A full-range speaker is designed to have as wide a frequency response as possible. These employ an additional cone called a whizzer to extend the high frequency response.

G

Gigabyte

A unit of information or computer storage equal to one billion bytes. It is commonly abbreviated GB in writing (not to be confused with Gb, which is used for gigabit) and gig in writing or speech. There are two slightly different definitions of the size of a gigabyte in use:

• 1,000,000,000 bytes or 10⁹ bytes is the decimal definition used in telecommunications (such as network speeds) and some computer storage manufacturers (such as hard disks and flash drives).
• 1,073,741,824 bytes, equal to 10243, or 230 bytes. This is the definition used for computer memory sizes, and most often used in computer engineering, computer science, and most aspects of computer operating systems.

Ground

In electricity ground is the ultimate destination of electrons, electricity will seek the path of least resistance to ground. Electric ground is noted as negative electricity.

H

Harmonic Distortion

Harmonics are added frequencies in multiples of the original frequency. Harmonic distortion is when the electronics responsible for your sound reproduction are creating harmonics. Electronic components are rated for an allowable amount of Harmonic distortion generated with normal operation. The sum of all the harmonic distortions created by the component is that components THD or Total Harmonic Distortion.

HAVi

(Home Audio Video interoperability) A format used for FireWire, generally found on Home Theater PC's. HAVi software makes PC devices compatible with Home Theater audio and video.

HD DVD

(High Definition Digital Video Disc) HD DVD is a next-generation optical disc format meant for storage of 15 gigabytes (GB) of high-definition video or data. Jointly developed by a group of consumer electronics and technology companies called the DVD Forum. Currently involved in a format war with the Blu-ray disc format.

HD-Ready TV

A European standard with two forms. 'HD Ready' TV's can handle a high definition input signal (e.g. 1080i or 1080p) and display a minimum of a 720p picture. 'HD Ready 1080p' TV's can also display a 1080p picture. For more information, see here.

HDCP

High-bandwidth Digital Content Protection - used to encrypt and protect content transmitted over HDMI or DVI connections. For more information see here.

HDMI

High-Definition Multimedia Interface - a connector that carries combined digital audio and digital video or analog video. Capable of carrying high-definition signals such as 720p, 1080i and 1080p. For more information see TV Connectors or a more detailed explanation of HDMI here.

HDTV

(High Definition Television) A generic term for any television signal that contains a resolution of 720 horizontal lines or greater (e.g. 1080i, 1080p). For more information about display resolutions see here.

Hertz

(Abbreviated Hz) Named for German physicist Heinrich Hertz (1857-1894) who artificially produced electromagnetic waves. Hz has become a standard measure of frequency, 1 Hz = 1 cycle per second.

High Definition

'Definition' is a measure of a displays resolution. TV displays with a resolution of 720p or above are classed as High Definition. Displays with a resolution below 720p are referred to as standard definition and enhanced definition. The high definition resolutions available on the market today are 720p, 1080i and 1080p. For more information on display resolutions see here.

High-End

Equipment that is designed to be the best it can be, regardless of price. To some people, high-end could be any mainstream electronics manufacturer's flagship (most expensive) model. To others, high-end is exclusively the domain of rare brand names producing expensive units found only in speciality stores.

Horizontal Resolution

The number of vertical lines in your video monitor's picture is horizontal resolution. Horizontal and vertical resolutions are named counter intuitively, horizontal resolution is the number of vertical lines in the picture and vertical resolution is the number of horizontal lines in the picture.

Horn

A type of loudspeaker found in some Home Theater speaker systems. Small driver sits inside the back end of the horn (like a bullhorn used by police to talk to crowds at the local riot) sound waves from the driver are directed forward by the horn. This design is well used in Home Theater not only for it's great efficiency for creating decibels but also it's forward impacting sound.

HTPC

(Home Theatre PC), also known as an 'Entertainment PC', this is a PC connected to a TV as part of a home entertainment system. A popular operating system used on these PC's is Windows Media Center Edition (MCE).

Hue

The attribute of color that shifts the balance of color between the primary colors red, yellow and blue. Some TV's have a hue setting to adjust the colour balance.

Hum

(Also called; 60 cycle hum) This is generally noise in audio equipment from unfiltered AC power coming from the wall. The hum is the audible 60 cycle frequency from the 120v AC that delivers power to our households. Its presence in your audio is an indication of leakage from your power supply.

Hz

See Hertz.

I

IEC 169-2 Connector

A low quality aerial connector used on most TV's and VCR's.

IEEE

(Institute of Electrical and Electronic Engineers) An organization that develops communications and networking standards.

IEEE 1394

See FireWire.

iLink

See FireWire.

Imaging

(Also Soundstaging) In Home Theater audio, imaging is the ability to create the illusion of width and depth in sound. Imaging was first employed between two speakers in stereo, when sounds from the two speakers worked in synch a wider sonic image was created. Two channel stereo quickly became the dominant audio recording standard for music. For Home Theater three, four, five and up to seven channels working in synch create the attribute of surround sound. Sonic imaging is the most important aspect to "surround sound" and can be perfected in your own Home Theater area by experimenting with speaker positioning and the relative size/shape of your Home Theater room.

Impedance

Integrated Amplifier

A power amplifier with a built in pre-amp. An archaic term generally used for two channel stereo. However a Receiver is just an Integrated Amp with added A/V switching, surround processing and a tuner all built in.

Interconnects

Interconnects refer to the standard RCA plugs used for connecting flat (not amplified) analog signals between audio components.

Interlace

A process that divides video into odd and even horizontal lines and alternates which are presented at one time. The alternation between the horizontal lies is fast enough so that to the human eye they appear as one solid image. The alternative to an interlaced video pattern is progressive scan where no interlacing takes place, which produces superior image quality.

ISDB

ISDB or Integrated Services Digital Broadcasting is the digital television and digital audio broadcasting format that Japan has created to allow radio and television stations there to convert to digital.

J

Jack

The female end of a connector as opposed to the male end of a connector which is a plug.

Jitter

Jitter can describe any distortion to an analog or digital signal but is generally used today to describe latency or interference to digital signals. "Digital" or "Binary Jitter" is latency in digital connections or network traffic over long distance runs. The term is misused in Home Theater and Hi-Fi to sell expensive digital cables to unwary consumers.

K

Keystone Correction

Adjustments in a projector that corrects distortions to the image due to projecting images at an angle.

Keystoning

Image distortion from a projector due to projecting the image at an angle. It causes the images to appear in a trapezoidal shape narrow at either the top or bottom depending on the angle of the projector. This can be adjusted by Keystone Correction controls in the projector to give the projector placement flexibility.

L

Laserdisc

(LD) 12 inch optical disc that looks like an oversized CD, early 90's technology replaced by the DVD. The Laserdisc stored analogue information (both audio and video) on both sides of the disc, limited to about 60 minutes per side.

LCD

(Liquid Crystal Display) A fixed pixel display device renowned for energy efficiency and colorful high contrast images. LCD displays may suffer from dead pixels and LCD projectors can suffer from "screen door" effects. Neither form of LCD is as good at displaying black as CRT.

LCoS

(Liquid Crystal on Silicon) A projection TV display technology that sandwiches a layer of liquid crystal between a cover glass and a highly reflective, mirror-like surface patterned with pixels that sits on top of a silicon chip. These layers form a micro-display that can be used in rear-projection TV's.

Learning Remote

A type of Universal Remote Control device that is able to receive infrared signals from other remotes to imitate the IR pattern. Assigning the commands from other remotes to buttons on the Learning Remote gives it invaluable flexibility as a universal remote.

LED

(Light Emitting Diode) Used on display panels on the front of electronic components. Valued for low power requirements and longevity. Also used as a method of backlighting some TV displays (e.g. LED TV's).

Letterbox

The term given to video (usually from a theatrical release) that is wider than a regular TV aspect ratio and shrunk down so the entire width fits inside the narrower screen. The consequence to letterboxing is the wasted space on the top and bottom of the image appearing as "black bars" on the top and bottom of the screen.

LFE

(Low Frequency Effects) One of the channels in multi-channel audio that carries low frequency (i.e. bass) frequencies ranging from 10Hz to 120Hz. This channel is usually sent to the subwoofer (if present). For more information see here.

Lossless

Data compression algorithms that reduce the size of digital content with no loss of information. There are no common lossless video formats in use, but Common audio formats include ALAC (Apple Lossless Audio Codec), FLAC (Free Lossless Audio Codec), and WMA Lossless (Windows Media Lossless). The opposite of lossless data compression is lossy data compression.

Lossy

Refers to the digital compression of information where some of the original information is lost. Unlike lossless compression, an exact copy of the original information cannot be reconstructed. Examples of lossy data compression include MP3 and MPEG-2.

Luminance

That part of a video signal relating to the degree of brightness at any given point in the video image. If luminance is high, the picture is bright and if low, the picture is dark. The luminance signal in component video such as YPbPr represents the black and white portion of the picture.

M

Macrovision

A digital rights management (DRM) system to prevent copying of DVD-Videos onto video tape. The technology is named after the company that developed the technology.

Matrix Decoding

(Matrix channel) Extracting one or more channels of sound from exiting channels of sound. An example is how stereo left and right channels of sound carry the information used for the center and rear channels in a dolby pro-logic surround system. The alternative to a matrix channel is a discreet channel which is not made up of sounds from another existing channel.

MCE

(Windows Media Center Edition) An operating system based on Microsoft Windows XP. MCE has a display mode designed for viewing on a TV as part of a Home Theatre PC (HTPC). For more information see here.

Microphone

A device that turns sound waves into electrical signals, the very opposite of a loudspeaker.

Midbass

The name given to the audible range of medium low frequencies. Generally around 50 to 100 Hz is considered midbass.

Middle Highs

The name given to the medium high range of audible frequencies. Generally considered to be around 2.6-5kHz.

Midrange

The name given to the middle range of audible frequencies around 200-3kHz.
Also known as a 'squawker', the name given to the speaker responsible for reproducing this range in a speaker system.

Minidisc

(MD) A digital audio format created by Sony. Small plastic discs containing compressed digital audio information. Despite lukewarm consumer response to the MD format in North America the Minidisc has seen tremendous popularity in Japan.

Monaural

(Mono) A single channel recording and sound reproduction method. Single speaker TV sets are said to be mono.

MOSFET

(Metal Oxide Semiconductor Field Effect Transistor) A field effect transistor that is controlled by voltage instead of current. Used in some power amplifiers for high power and efficiency.

MLP

(Meridian Lossless Packing) Developed by Meridian Audio, this is the encoding technology used in DVD-Audio, HD-DVD, and Blu-ray discs. The standard supports a maximum 63 channels of 96 kHz/24 bit audio, but most implementations are use a maximum of 8 channels.

MP3

A popular format of compressed audio. These compressed audio files are small therefore easily transmitted across the Internet. The MP3 is a lossy compression format.

MPAA

(Motion Picture Association of America) The body that governs the US film rating system. Most movies are made to fit into one category of the MPAA's rating system depending on the relative age of its target audience. The MPAA has gained a high degree of public attention due to its campaign against movie piracy.

MPEG

(Moving Pictures Experts Group) pronounced 'EM-peg' this is a working group of the International Organization for Standardization (ISO) & the International Electrotechnical Commission (IEC), that developed the compression for audio and video used on DVDs. MPEG has standardized the following compression formats and ancillary standards:

• MPEG-1: Initial video and audio compression standard. Later used as the standard for Video CD, and includes the Layer 3 (MP3) audio compression format.
• MPEG-2: A transport standard, & lossy video and audio compression standards for DVD and digital TV.
• MPEG-3: Originally designed for HDTV, but abandoned when it was discovered that MPEG-2 was sufficient for HDTV.
• MPEG-4: Expands MPEG-1 & MPEG-2 to support video/audio "objects", 3D content, web (streaming media), conversational content (videophone), & support for Digital Rights Management (DRM).
• MPEG-7: A formal system for describing multimedia content. MPEG-7 is not used for the compression of information, instead it uses XML to store metadata, and can be attached to timecode in order to tag particular events, or synchronise lyrics to a song, for example.
• MPEG-21: MPEG-21 is not used for the compression of information, instead it uses XML to share Digital Rights Management permissions/restrictions for digital content.

For more information see the MPEG homepage.

Muddy

A qualitative term used for bass reproduction that is muffled or unable to quickly change from very low to medium low frequencies as the soundtrack demands.

N

Native Resolution

The actual number of physical pixels in the display device. The native resolution is the image resolution a device can reproduce without scaling. Fixed pixel displays such as Plasma, LCD, and DLP displays have a single native resolution but can accept most other resolutions by upscaling or downscaling the signal to fit its native format.

Neutral

Adjective used to describe the sonic quality of a speaker system that reproduces sound as naturally as possible, free of any sonic coloration or qualities introduced by the speakers themselves. Neutral is only an ideal and shouldn't be taken literally, all speakers give some sort of coloration. Few manufacture's even try for a true neutral sound, partly because it's a practically unattainable goal. Even if the speakers themselves could create the perfect neutral sound there are acoustic environmental variables almost certainly preventing this in the room they're being played. Most people (without realizing) don't really want a neutral sound. This is why speakers are usually made with some coloration usually they try produce speakers to sound warm For less expensive Home Theater they will sometimes go for a knowingly harsh acoustical quality because harsh gets noticed on the showroom floor.

NTSC

(National Television System Committee) The US government industry committee that defined the technical specifications for US broadcast television over 50 years ago. NTSC also refers to the analog television standard it developed, which is also used in Canada, Japan, and South Korea. NTSC is being superceeded by the ATSC digital television standard.

O

Objectivist

In audiophile circles an objectivist is one who is either suspicious of claims of immeasurable acoustical qualities in an audio system or simply doesn't believe they can exist. The opposite of a subjectivist or the views expressed by a "Stereophile".

Ohm

The measure of resistance to the flow of electrons through a circuit. One part of the total sum of a circuit's impedance.

OLED

Organic Light Emmiting Display - a display technology where each pixel on the screen is made up of either a red blue or green organic light emitting diode (LED), which when stimulated by electricity fluoresce, producing coloured light. Unlike LCD and LED displays, OLED TV's require no backlight, making them extremely energy efficient.

Optical

The transmission of a signal using light. Types of optical signal include optical pick up (laser) on a DVD or CD player, and the TOSLINK optical cables used to connect audio components together.

Organic Light Emmiting Display

See OLED

Out of Phase

In electronics two cyclic motions are out of phase when they're not at the same part of their cycle at the same time. Speakers are out of phase when they're hooked up incorrectly, one speaker has the polarity reversed in the speaker's connection to the amplifier.

Oversampling

Digital playback equipment such as DVD or CD players might oversample by increasing the sample frequency (the frequency from which it reads information from the disc) several times. The desired outcome is better sound, a sort of false higher resolution from a 16bit sample. This was a popular advertised feature years ago on CD players but has since fallen out of favor so you'll rarely see electronics exclaiming "oversampling" as a bonus feature. There is no empirical evidence the technique provides any better sound.

P

PAL

(Phase Alternative Line) The analog television broadcast standard used by the majority of countries, common outside of North America, the format is an alternative to NTSC and SECAM. A PAL signal displays 625 interlaced horizontal lines at 50 Hz.

Pan and Scan

When a movie originally shot in widescreen format for a theater is converted to the narrow screens of standard TV they use the pan and scan technique. The picture is zoomed in so the viewers perspective gets panned around the larger original images to focus on what the video technician deems is the most important part of the scene.

Panavision

The brand name for a widescreen aspect ratio (2.35:1) filmed on 35mm with anamorphic lenses.

Passive Radiator

A speaker that is not electronically connected to any signal with no magnet or voice coil, just the cone mounted into a speaker box with other driven loudspeakers. It's designed react to the drivers it's aligned with to provide deeper bass, works like a port.

PCM

(Pulse Code Modulation) The standard for digitally encoding analogue signals, used for CD and DVD technologies.

Personal Video Recorder

(PVR) A video recorder that records from incoming TV signals (which can be cable TV, antenna, satellite) onto a hard disc in a digital MPEG format. You can record events like a VCR but you can also pause shows in progress and rewind back to a certain point while your watching. These features are available because it caches while your viewing, and records over the cache as you either come to the end of the drive or cache capacity or change the channel. TiVo and ReplayTV are well known subscriber DVR systems but many cable boxes and satellite receivers are featuring DVR capabilities.

PIP

See Picture In Picture.

Picture In Picture

A feature on some TV sets that allows a secondary video input to be displayed in a small frame within the main screen images. The audio for the smaller frame can generally be switched to, or listened to via headphones.

Pixel

The smallest element of a picture on a monitor or TV. A single dot that can be changed in color or brightness relative to the whole picture.

Plasma TV

A large flat panel display with better screen resolution and colour reproduction than a standard CRT TV.

Plug

The male side of a connector is a plug. The female side is a Jack.

Polarity

Identified as positive or negative for the 180-degree phase difference within the same audio signal. Polarity must be consistent when wiring speakers or audio components together; negative always matches negative, positive always to positive. To get them crossed at some point will cause sound that is "out of phase" and will limit frequency response.

Ported Speakers

A type of speaker enclosure that uses a duct or port to improve efficiency at low frequencies.

Power Output

The total power output is the measure in watts of an amplifier's energy output. Contrary to popular belief this is not directly proportionate to the loudness an amplifier can attain. Power Output must be considered together with speaker's efficiency (see: Efficiency Rating) to get an idea of how many decibels an amp can produce.

Preamplifier

Originally, the required amplification the tiny signal produced by a phonograph so that signal can be sent to the amplifier for further amplification. Today the preamplifier refers to the whole section of an audio circuit that controls switching between components and volume. The preamplifier is the control center of the component audio system and one of the many jobs performed by a Home Theater receiver.

Progressive Scan

The display of all horizontal lines in an image simultaneously. In an image being refreshed at 60 Hz, each horizontal line is drawn 60 times per second. Usually found in high-end TV's and projectors, and DVD players that have component video, DVI, or HDMI outputs. Progressive scan images look clearer, and are less affected by flicker than an interlaced signal running at the same frequency.

Projector

A system for projecting a video image from a smaller source onto a larger surface. This can be contained behind the display screen directed onto the screen via system of mirrors such as a "rear projection" TV, or directly onto a screen in front of the audience like a projector. LCD, LCoS and CRT technologies can all be used in projection televisions to generate the image to be projected.

PVR

See Personal Video Recorder.

Q

Quad Shield Cables

A type of coaxial cable with four layers of insulation instead of the usual two. The extra shielding reduces interference. Also known as a RG-6/UQ cable.

R

Rainbow Effect

On DLP projectors and rear projection TV's, the rainbow effect is created by the inability of the DLP color wheels to refresh pixels fast enough, resulting in some color separation on the edges of fast-moving objects.

Rear Projection

TV design where the projected image is passed through a screen to the viewer. To reduce the size of the TV case, mirrors may be used to "fold" the image to the screen. For more information see the Rear Projection page.

RCA

Also referred to as a phono connector or CINCH/AV connector, is a type of analog electrical connector which is commonly used in the audio/video market. The name "RCA" derives from the Radio Corporation of America, which introduced the design by the early 1940s to allow phonograph players to be connected to radios. RCA jacks are often color coded, yellow for composite video, red for the right audio channel and white or black for the left audio channel. For more information see here.

Receiver

In electronics a receiver is any component that is capable of receiving transmission and displaying in a viewable or listenable format. Television and radio receiver are terms that have been around a long time. In Home Theater a receiver is the component that does several operations at once for your audio system. Amplifier, preamplifier, surround processor often it is also a radio tuner and can even switch between video sources as well as audio sources.

Redbook CD

Redbook is the technical standard for encoding audio CDs that receive the 'Compact Disc Digital Audio' logo.

Refresh Rate

The number of times per second, during which a displayed image is regenerated, expressed in Hz. A low vertical refresh rate produces visible flicker.

Region Coding

Used by studios to control DVD release dates by geographic regions of the world, DVD players are designed to play DVDs their respective region only. The geographic regions are:

• Region 1: United States, Canada.
• Region 2: Japan, Europe, western Asia and South Africa (Turkey, Egypt, Saudi Arabia, South Africa).
• Region 3: Korea, Thailand, Vietnam, Borneo, Indonesia.
• Region 4: Australia, New Zealand, Mexico, Caribbean, South America.
• Region 5: India, Africa, Russia (nations of the former USSR).
• Region 6: Peoples Republic of China.

Resistance

Resistance to the flow of electrons through a circuit measured in Ohms. Resistance is the natural by-product of a circuit. Resistance is one part of a circuit's total impedance).

Resolution

The density or amount of detail in audio or video. The number of scan lines or pixels in a given image size is a video resolution, e.g. 1280x720 refers to 720 horizontal lines, each composed of 1280 pixels, giving a total of 921,600 pixels. For more information see here.

Resolution can also apply to digitally encoded audio as the number of bits and cycles per second, i.e. 24/96 KHz, which refers to 24 bits of information captured or expressed 96 thousand times per second.

Response Time

It is a measure of the time it takes for a pixel to turn on and off, or in simpler terms, how long it takes a display to change the image on the screen. Response Time is measured in milliseconds (ms), and is generally only a problem for LCD displays. A slow response time is noticeable when watching fast moving images like sports or computer games, and appears as a smearing of the image. A response time of 16ms is OK, but a response time of 8ms or less will largely eliminate display problems.

RF

(Radio Frequency) Radio Frequencies are electromagnetic frequencies passed as signals through the air. These can be received with a tuner capable of extracting the audio/video information to be played back. RF that is a side effect of electronic devices and naturally occurs in the atmosphere as noise it's called EMF (electromagnetic frequencies).

RF Connector

An electrical connector designed to work at radio frequencies (RF) in the multi-megahertz range. RF connectors are generally used with coaxial cables and come in a variety of connector formats. Common forms include the IEC 169-2 and F connectors.

RFI

(Radio Frequency Interference) RFI is any RF or EMF shows up as noise in electronic circuits. A common example is the low level hiss in speakers, or interference in aerial cables caused by the presence of other (usually power) cables.

RGB

A video signal that is broken down into three separate parts (along three cables) for transmission. Also called component video, along with DVI-A, this is the best method for transmitting an analogue video signal. For more information see here

Ribbon Speaker

Also called Planar Magnetic speaker. Ribbon is specifically the type of planar magnetic speaker made of soft materials and never metal.

RMS

(Root Means Square) The square root of mean (average). RMS refers to the "continuous" power output of an amplifier that is, not counting the amplifiers ability to compensate for spikes in an audio soundtrack. An amp's RMS power output is the level power it's rated to continuously provide to speakers.

RPTV

(Rear Projection Television) Any TV that employs projection within its own box to increase the size of the picture. This is accomplished with mirrors, lenses and a screen onto which to display the picture to the audience. Usually RPTV's are large TV sets from 40" and up and aren't limited to any one display type. RPTV's can be CRT, LCD or LCoS or DLP.

S

S/PDIF

(Sony/Philips Digital Interface) The format for transmitting digitally encoded audio between components in a Home Theater system. The signal is transmitted through a digital coaxial or optical TOSLINK cable. For more information see TV Connectors.

SACD

(Super Audio CD) A high resolution 2.0 & 5.1 channel audio disc developed by Sony & Philips. SACD differs from its competitor DVD-Audio in that it does not use Pulse Code Modulation (PCM) to digitally encode the high resolution audio signal but instead uses Sony's proprietary Direct Stream Digital (DSD) technology. While technically superior to CD's (CD's have 1/7th the data capacity and a much lower and a much lower 16-bit/41.1 kHz bitrate), SACD never gained much consumer acceptance, and titles are limited. For more information see here.

Sampling

How analog information is encoded digitally in either video or audio. A sample is a small portion of the analog information taken at a regular interval (rate).

Sampling Rate

The rate at which a sample is taken measured in Hz (cycles per second).

SAP

(Secondary Audio Program) A secondary audio signal on a television channel commonly used as a means of providing bilingual programming.

Saturation

Used many different ways but basically always means something is full and can no longer respond to an external influence. In video saturated colors are vivid and pure. In electronics saturation of an amplifier occurs when output transistors are pushed beyond capacity and the output is no longer a linear amplification of the input, distortion results.

Scan Lines

The horizontal lines making up a picture on a CRT TV or projector. See Horizontal Resolution.

Screen Door

The fine grid of thin dark horizontal and vertical lines resulting from the gaps between pixels in a (usually projected) picture generated using digital displays such as LCD.

SDTV

An acronym for Standard Definition Television. This is a digital TV that can display a progressive scan picture made up of 480 or 576 horizontal lines. For more information on display resolutions see here.

Sealed Speaker

(See Acoustic Suspension Speakers) A type of speaker that contains cone drivers with no ports.

SECAM

(Séquentiel couleur à mémoire) French for "sequential color with memory", SECAM is an analog color television system first used in France. It is, historically, the first European color television standard. SECAM is common in the former French colonies, and Eastern Europe.

Sensitivity

A measure of speaker's efficiency. Determines how loud the speaker will perform in decibels from a specific input power rating. The accepted rating method for 8ohm speakers is the number of decibels from one meter away from the speaker with 1 Watt input. (4ohm speakers would simply double the power requirement for the same number of decibels). Speaker sensitivity is an important factor in how loud your system will go but has no bearing on sound quality.

Set Top Box

Refers to a box that sits on your TV set used for decoding or tuning. This can be a digital TV decoder, cable box, satellite receiver or any external decoder, processor or digital video recorder.

Sharpness

A video setting on TVs that will pronounce the difference between light and dark images on the screen. Turning up sharpness should create greater contrasts where turning it down softens the overall picture. Sharpness is not the same as a focus control, it does not make the picture any "better" per se, this is a setting best left about halfway.

Sibilance

The distortion of the S sound, an acoustic problem with speaker's reproduction of middle-high pitched sounds. You can easily listen for sibilance with high quality recordings of a female singer perform with little background music, listen for her to make the S sound and how clearly the speaker is capable reproducing this. It's a very important test when auditioning a new set of speakers.

Signal

Alternating currents that carry useful information such as audio, video or both.

Signal-to-Noise Ratio

(S/N) A measurement of the difference in decibels between noise present in an amplified audio signal and the sounds being reproduced. The higher the number the better as there will be a higher number of decibels of good sound over noise produced by the playback components.

Soft Dome Tweeter

A design of tweeter in a speaker system where the tweeter is made from a soft material usually a fabric that makes up the diaphragm.

Solid State

Refers to electronics that use semi-conductors instead of vaccum tubes. Amplifiers today can still be made from vacuum tubes - particularly in the high-end (expensive) category. Those that don't use vacuhttps://www.google.com/adsenseum tubes will use transistors and will be called solid state.

Soundstage

Simply the area of sound created by a Hi-Fi system. Soundstage usually refers specifically to the illusions of space and positioning of sounds from a Home Theater system. To experience the soundstage speaker positioning is essential.

Source

The original signals received by a HomeTheater system. Source material can come from a satellite dish, antennae, DVD. Source components are those that playback the source, IE: DVD Player, Satellite receiver, Cable box or even your TVs tuner.

SPDIF

See S/PDIF.

Speaker

(Loudspeaker) The component in a Home Theater system that converts electrical energy into sound.

Spike

A spike is a portion of a signal that goes above the normal. A spike in a soundtrack is a point where the sound requires more energy to properly reproduce than normal. A spike can occur when a lot of loud sounds happen at once in a film and can cause output transistors in your amplifier to clip due to saturation.

SPL

(Sound Pressure Level) This is a meter you can purchase at low cost that measures the level of sound pressure in decibels. An effective tool for tuning a Home Theater system.

Squawker

See midrange.

Standard Definition

'Definition' is a measure of a displays resolution. Displays with a resolution of 480i to 576p are classed as Standard Definition. For more information on display resolutions see here.

Standby

A mode where a TV or other appliance powers down and draws minimal power. The appliance can then be reactivated via a remote control or a signal from another appliance.

Stereo

Two channel audio system. Stereophonic sound revolutionized home audio when it was introduced 50 years ago. It gave a sense of heightened realism by presenting a soundstage that gave music width and added dimension over convention mono sound.A popular magazine dedicated to subjective reviewing of very expensive audio equipment. Stereophile has become more of an attitude in Hi-Fi representing the more-expensive-the-better approach in a quest for a "perfect sound".

Stereophile

A popular magazine dedicated to subjective reviewing of very expensive audio equipment. Stereophile has become more of an attitude in Hi-Fi representing the more-expensive-the-better approach in a quest for a "perfect sound".

Subjectivist

An audiophile who believes there are attributes to high fidelity audio that aren't measurable.

Subwoofer

A speaker system designed to reproduce bass frequencies from about 5Hz to about 90Hz. Frequencies 16Hz or lower are more felt than heard. Usually comprised of a single large driver and a ported box, the subwoofer can be self amplified or driven by an external amp.

Surround Sound

A generic term that refers to one of several standards of multi-channel audio used in Home Theater, including:

• Dolby Pro Logic
• Dolby Digital
• DTS (Digital Theatre System)

Surround Speaker

Surround speakers refer to the rear speakers in a Home Theater system. Surrounds are classically smallish speakers even though today's surround formats can produce full range audio they're still not used as much as the front or center speakers.

SVCD

(Super Video Compact Disc) An enhancement to the VCD format, SVCD's are recorded on a CD-R and have two-thirds the resolution of DVD, and over 2.7 times the resolution of VCD. Video is stored at 480x576 pixels for PAL and SECAM, and 480x480 pixels for NTSC. One CD-R disc can hold up to 60 minutes of SVCD-format video, though it is possible to fit additional video by lowering the video bitrate. SVCD's use the MPEG-2 standard for video encoding, and the MPEG-1 Layer 2 audio format.

S-Video

(Super Video or Y/C) A video connection standard where luminance and colors are separated and transmitted separately within the same cable. For more information see the here.

Sweet Spot

The best place to sit for the full effects of a Home Theater system's sonic and video effects. This will be the point at which the sounds from all speakers in a Home Theater converge at the same time. The sweet spot is usually a small circle in the middle of the listening area directly in front of the TV.

T

Tape Monitor

The connection on your receiver that has both input and output designed to loop into your circuit for the purposes of recording while listening to another source.

Three-line Digital Comb Filter

A powerful microprocessor that provides enhanced picture detail by comparing and adjusting three different lines of video information simultaneously. See also comb filter.

THX

Not a format but a standard created by Lucasfilm for motion picture viewing. The standard takes into account several aspects including audio and video and sets specific requirements for how these are presented. Higher quality Home Theater equipment has the THX logo which just means it's certified by Lucasfilm that it meets the THX standards.

Timbre

A qualitative characteristic of audio introduced by your choice in speakers. Timber can be called color of sound from your speakers, timber tends to be unique to speaker designs and manufacturers.

Timbre Matching

Using speakers of similar timbre through your Home Theater system is timbre matching. Timbre matching is just about guaranteed when you purchase a speaker system where all the speakers are by the same manufacturer designed to work together, but it's not the only way to get good timbre matching. Well matched speaker sets will make sound consistent as audio makes the transition from speaker to speaker.

TOSLINK

A fiber optic cable used for digital connection between audio components. The data in a TOSLINK cable is transferred using S/PDIF connection. For more information see here.

Treble

High pitched sounds or "highs". Generally anything greater than 3kHz is treble.

Triad

A group of three horizontal phosphor lines on the display of a CRT TV or computer monitor. The triad is composed of coloured red, green, and blue lines. By directing differing amounts of electrons onto the three phosphor lines, the triad will display a colour by combining the red, green and blue elements. The height of a triad plus the distance between triads is known as the dot pitch.

Tuner

Part of your receiver that tunes in radio stations. There are standalone components for audio systems called tuners dedicated for this purpose.

Tweak

To fine tune your audio system by employing improvements or methods believed to improve sound.

Tweeter

A loudspeaker which is capable of reproducing the higher end of the audio spectrum, usually from about 1kHz to 20kHz.

U

Universal Remote Control

A large programmable remote control capable of controlling several components in your Home Theater system such as digital TV decoders, cable boxes, satellite TV systems, DVD players, VCRs and surround sound receivers.

Upconversion

See upscaling.

Upscaling

Increasing the number of pixels in a signal by extrapolation so that it matches the native resolution of a display. An upconverted signal doesn't have any information added, so the overall quality is limited to that of the original. An example would be the upscaling of a DVD signal by a 1080p TV. Upscaling is the opposite of downscaling.

V

VCD

(Video Compact Disc) A forerunner to the DVD. VCD's are recorded on CD-R media (the same as compact discs). As they use the same bitrate as a CD, VCD's have the same playing time, around 74 minutes of video and audio. Overall picture quality is intended to be comparable to VHS video, though poorly compressed video in VCD's tends to be lower quality than VHS video. VCD's are playable in almost all DVD players. The video resolution is 352x288 pixels (PAL) or 352x240 pixels (NTSC), approximately one quarter of full TV resolution (720 × 480 and 720 × 576 respectively). VCD uses the MPEG-1 standard for video encoding, and the MPEG-1 Layer 2 audio format. The VCD format was later enhanced to create SVCD standard.

VCR

(Video Cassette Recorder) An appliance used to record video and audio on VHS cassettes.

Vertical Resolution

The number of horizontal lines in your video monitor's picture is vertical resolution. Horizontal and vertical resolutions are named counter intuitively, horizontal resolution is the number of vertical lines in the picture and vertical resolution is the number of horizontal lines in the picture.

VHS

(Video Home System) a recording and playing standard for video cassette recorders (VCRs), developed by JVC.

Viewing Angle

The maximum angle (looking from the left, right, above and below) at which viewers can clearly see an image on the screen. Sometimes defined as the measure in degrees at which a display's brightness drops to 50%.

VGA

Voice Coil

A part found in a conventional loudspeaker. The coil and magnet work together to drive a diaphragm that pushes air into the front of the loudspeaker.

W

Watt

A unit of energy or heat, one horsepower is 745.7 watts. Amplifiers deliver watts only when they must drive speakers as it is only when driving speakers are they confronted with a workload measurable in watts. This is the reason that watts vary in reverse proportion to variation of resistance of the speakers. Less resistant speakers (rated at fewer ohms) require more watts to drive.

Watts Per Channel

The Federal Trade Commission in North America has determined that amplifiers sold will have a power rating in watts per channel through an 8ohm load.

Whizzer

A small, light cone attached to the woofer's apex around the dust cap.

Widescreen

Video displayed in any format wider than the conventional TVs 4:3 standard. Usually this means 16:9, the same as the movie theater. (See Aspect Ratio).

WinMCE

See MCE.

Windows Media Center Edition

See MCE.

WMA

(Windows Media Audio) Microsoft's version of an MP3. Audio files encoded in the WMA format carry the extension *.wma.

Woofer

A speaker that is designed to handle the low end of the audio spectrum, generally 50Hz to 1KHz, though some may go as high as 3KHz. Woofers can reproduce sounds just short of the subwoofer's capabilities.

Y

YCbCr

A component video format which uses three separate video signals to reduce interference and improve picture quality:

• Y - luminance or the black and white portion of the picture.
• Cb - blue chrominance component.
• Cr - red chrominance component.

Also known as YCC. Similar in concept to the YPbPr signal encoding format, YCbCr comes in both a digital and analog format.

YCC

See YCbCr.

YIQ

The colour space originally used in the analog NTSC television broadcast system. YIQ was eventually replaced by the YUV colour space.

YPbPr

A component video format which uses three separate analog signals to reduce interference and improve picture quality:

• Y - luminance or the black and white portion of the picture
• Pb - Blue minus luminance color difference (also abbreviated as BY)
• Pr - Red minus luminance color difference (also abbreviated as RY).

Also known as Component, YPrPb, PrPbY, and PbPrY. YPbPr is similar in concept to the YCbCr video signal format used for digital and analog video connections.

YUV

The colour space used in the analog PAL and NTSC television broadcast systems. NTSC originally used the YIQ colour space, but it was eventually replaced with YUV.

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