Converts film footage to NTSC standards (Film footage is shot at 24 frames per second; NTSC standards for video require 30 frames per second). 3:2 pulldown refers to the electronics needed to convert 24 FPS to 30 FPS so that it can be viewed on a NTSC video device (such as a television).

A sealed or closed box speaker enclosure.

There are only three classic (physical) tools available for the acoustician to treat a room: absorbers, reflectors and diffusers. Absorbers attenuate sound; reflectors redirect sound, and diffusers (hopefully) uniformly distribute sound. However, with today’s advanced digital audio tools, all of these elements can be electronically manipulated.

An electrical current that periodically changes in magnitude and direction.

A type of high-definition plasma TV panel designed for optimum performance when displaying 1080i material. On a typical progressive-scan plasma TV, all pixels can be illuminated at any given instant. With an ALiS plasma panel, alternate rows of pixels are illuminated so that only half the panel’s pixels can be illuminated at any moment (somewhat similar to interlaced-scanning on a CRT-type TV).

The acoustic characteristics of a space determined by reverberation. A room with a lot of reverb is said to be “live;” one without much reverb is “dead.”

The sound that exists in a room that does not come from a loudspeaker, musical instrument or some other intentional sound source.

The standard measure of electrical current flow. One amp is equal to one Coulomb of charge flowing past a point in one second.

A device which increases signal level. Many types of amplifiers are used in audio systems. Amplifiers typically increase voltage, current or both.

The peak-to-peak size of a waveform. For audio purposes, the greater the amplitude of the signal, the louder the sound will be.

Refers to widescreen video images that have been “squeezed” to fit a narrower video frame when stored on DVD. Most of today’s TVs employ a screen with 16:9 aspect ratio, so that anamorphic and other widescreen material can be viewed in their proper proportions.

A representation of sound waves that is continuous. In contrast, digital representations consist of values measured at discrete intervals.

Echo free. An anechoic room has no reflected sound. This is accomplished by treating all of the room’s surfaces with sound absorbing material.

Artifacts are defined as unwanted visible effects in the picture caused by disturbances and errors in the video transmission or digital processing. Artifacts include “edge crawl” or “dot crawl” or “hanging dots” in analog pictures, and “pixelation,” “contouring” or “blockiness” in digital pictures.

Aspect ratio is the ratio of width to height of a television or display screen. Common aspect ratios are:
4:3 – Refers to the format used in traditional televisions and in most is only found on televisions equipped with NTSC tuners and non-High Definition displays
16:9 – Refers to the ratio of widescreen DTV formats for High Definition equipped televisions and displays.

Uneven or off center; not symmetrical. In speaker cabinet design asymmetry can be beneficial as it reduces the standing waves in the cabinet.

The acoustic spectrum of human hearing, generally regarded to be between 20Hz and 20kHz.

Using a TV’s direct audio/video inputs to connect a DVD player, VCR, camcorder or other video component provides improved picture and sound quality compared to using the everything-on-one-wire RF antenna-style input.

(Advanced Television Systems Committee) developed standards for digital television (DTV) in the U.S, Canada, South Korea, Taiwan and Argentina. The ATSC system supports a host of different display resolutions and frame rates.

For speakers, the imaginary line that runs from the speaker to the intended listener position.

On a speaker the baffle is the front plate the drivers are mounted on..

Bandwidth is the range of frequencies used for transmitting picture and sound information from the broadcaster’s transmitter to your TV. More common use of the term refers to the amount of information that can be carried in a given time period (usually a second).

Part of a speaker, typically of cast metal, that holds together the driver, magnetic structure, voice coil, cone and spider.

The low end of the audio frequency spectrum between 0Hz to about 200Hz.

A type of loudspeaker that uses a port or duct to augment the low-frequency response. Opinions vary widely over the “ best” type of bass cabinet, but much has to do with how well a given design, such as a bass reflex is implemented. See also: Ported Enclosure.

Bi-amping refers to the use of two separate amplifier channels connected directly to individual loudspeaker drivers. Bi- amping requires (usually) an external active crossover to separate the frequencies before sending them to the respective amps.

Speaker wire terminal on better amplifiers and loudspeakers; can accept multiple cable termination types. Superior to spring or wire-clip connectors.

Type of loudspeaker with drivers mounted on opposite sides of the cabinet, or speaker enclosure. Drivers move in and out together so they remain “in-phase.” Often used as rear-surround speakers. (Also see: Dipolar)

The use of two pairs of speaker wire from the same amplifier to separate bass and treble inputs on the speaker.

Measured as “bits per second,” and used to express the rate at which data is transmitted or processed. The higher the bit rate, the more data is processed and, typically, the higher the picture resolution. Digital video formats typically have bitrates measured in megabits-per-second (mbps). (One megabit equals one million bits.) The maximum bit rate for standard DVDs is 11mbps; for over-the-air HDTV broadcasts, it’s 19.4mbps.

Describes the appearance of darker portions of a video image. Black is the absence of light, so to create the black portions of an image a display must be able to shut off as much light as possible. Displays with good black level capability not only produces deeper blacks, but also reveal more details and shading in dark or shadowy scenes.

Is an industrial specification for wireless personal area networks (PANs), also known as IEEE 802.15.1. Bluetooth provides a way to connect and exchange information between devices such as personal digital assistants (PDAs), mobile phones, laptops, PCs, printers, digital cameras and video game consoles via a secure, globally unlicensed short-range radio frequency. A short-range radio technology aimed at simplifying communications among Internet devices and between devices and the Internet. Bluetooth has no native support for IP, so it does not support TCP/IP and wireless LAN applications well. It was not originally created to support wireless LANs. Best suited for connecting PDAs, cell phones and PCs in short intervals. Products with Bluetooth technology must be qualified and pass interoperability testing by the Bluetooth Special Interest Group prior to release.

Is a next-generation optical disc format designed for high-density storage of high-definition video and data. Blu-ray utilizes the 405nm-wavelength blue-violet laser technology, in contrast to the 650nm-wavelength red laser technology used in traditional DVD formats. The re-writable Blu-ray disc, with a data transfer rate of 36 Mbps, can hold up to 27 GB of data on a single-sided single layer disc (in contrast to the traditional DVD’s 4.7GB capacity), which amounts to about 12 hours of standard video or more than 2 hours of high-def video.

Burn-in can occur when a static image — like on-screen video game controls, a scrolling stock or news ticker, or a station logo — remains on-screen for an extended period (generally several hours).

A CableCard is a removable security card available through most cable TV providers. It allows a TV with a compatible CableCard slot to receive digital cable programming, including premium and HD channels, without using a separate set-top box.

A broadband transmission medium, most often using 75-ohm coaxial cable carrying many TV channels simultaneously.

The center channel speaker is used to produce the voices, dialogue, or any other sound effects the director mixes into it. In a home setting it is preferable to have the center channel speaker either directly on top of, or directly below, your television. It is important that the center channel is voice-matched to the front left and right speakers especially, if not also the rear left and right. This creates a seamless and convincing soundstage for movies.

Chrominance is a color term defining the hue and saturation of a color. It does not refer to brightness.

Minimize the amount of light reflected back to the lamp and the amount of ambient light that mingles with the focused light leaving the lens. Good coatings generally add 15% or more to the brightness of lenses.

Short for coaxial cable - a type of 75 ohm cable most commonly used for cable TV connections and with some antenna systems for FM radio and television. Also used to connect CD or DVD transports to DACs. May also be found as the basis for many video interconnect cables including Composite, S-Video, Component, and RGB.

The color resolution of HDTVs and other video gear is typically described as a color bit depth such as “8-bit” or “10-bit.” Color resolution indicates how fine the gradations can be between different shades of the same color. It’s a measure of color accuracy.

Color temperature measures the "whiteness" of a light source. Metal halide lamps have very high temperatures compared to halogen or incandescent lights.

A comb filter’s task is to remove residual chrominance (color) information from the luminance (brightness) signal. Comb filtering enhances fine detail, cleans up image outlines, and eliminates most extraneous colors from analog video signals.

Component Video is a method of delivering quality video (RGB) in a format that contains all the components of the original image. These components are referred to as luma and chroma: they are defined as Y'Pb'Pr' for the analog component format and Y'Cb'Cr' for the digital component format. Component video is available on certain DVD players, Projectors, and televisions.

A type of video signal in which all information—the red, blue, green signals and sometimes audio signals as well—are all combined together. This is the type of signal used by the NTSC standard.

Most projectors automatically accept images that are of a greater resolution than the native (true) resolution of the projector. The resulting image is scaled to fit the native resolution of the projector. Not all projectors use the same compression algorithms; therefore, the quality of compression can vary. The nature of compression in a digital device also means that some image content can be lost.

Compression allows the delivery of more programs in a single channel. It is an electronic manipulation of digital data that reduces and removes redundant and/or non-critical information in the digital picture and sound without noticeably degrading picture quality.

The conical diaphragm of a speaker attached to the voice coil that produces waves in the air that the ear detects as sound.

Defined as the ratio of the luminosity of the brightest (white) and the darkest (black) color a system is capable of producing. The higher the ratio, the greater the CRT, LCD, plasma, or projector’s ability to visually illustrate subtle color and detail.

Invented in 1897, even nowadays it is the most common display technology for televisions. The tube uses an electron beam to scan lines on the screen coated with phosphor, which glows when struck by the beam. The other display technology being used more and more often nowadays in television sets is LCD.

A Digital to Audio Converter. Converts a digital bitstream to an analog signal.

The attenuation of a resonant frequency over time.

Any material added to increase dampening. Acoustic fiberglass, polyester batting, or polyfill inside the speaker enclosure can be used to dampen the woofer cone’s resonant frequency.

(Directional Correlation Deinterlacing) is a digital enhancement method designed to improve low-resolution video. For example, it helps to eliminate jagged edges generated by interlaced video. The technique is often used in LCD and plasma television sets.

The measure of sound loudness. One dB is considered to be the smallest change in sound loudness that is perceptible to the human ear.

A color resolution standard associated with high-definition TVs and video gear that include HDMI 1.3 connections. Deep Color supports 10-bit, 12-bit and 16-bit color bit depths, up from 8-bit, which is the current standard for consumer video.

The process of converting an interlaced-scan video signal (where each frame is split into two sequential fields) to a progressive-scan signal (where each frame remains whole). De-interlacers are found in HDTVs and progressive-scan DVD players.

In a speaker, the part driven by the voice coil that moves, producing air waves that we perceive as sound. It usually has the shape of a cone or dome.

The representation of a waveform with bits of information that are discreet (non-continuous) in both time and amplitude. See PCM and Analog.

A connection found on HDTVs and HDTV tuners for sending the Dolby Digital soundtrack of HDTV broadcasts to an A/V receiver with Dolby Digital decoding. The two most common types of digital output are coaxial and Toslink optical.

(DTS) Another delivery format for digital surround sound, DTS competes against Dolby Digital. Favored by many, DTS uses less compression, on average, and strives to master a film’s original sound mix. Many motion picture studios, however, do not want to spend the extra money to include DTS on DVDs.

Audio distortion: The name given to anything that alters an original input signal other than changing its amplitude (loudness).

Acronym for do-it-yourself, usually referring to various hobbies, especially audio-related.

(Digital Light Processing) technology developed by Texas Instruments used by projectors and televisions. In DLP projectors, the image is created by microscopically small mirros laid out in a matrix on a semiconductor chip, known as a Digital Micromirror Device (DMD). Each mirror represents one pixel in the projected image. The rapid repositioning of the mirrors (essentially switching between 'on' and 'off') allows the DMD to vary the intensity of the light being reflected out through the lens, creating shades of grey in addition to white (mirror in 'on' position) and black (mirror in 'off' position). There are two primary methods by which DLP projection systems create a color image, those utilized by single-chip DLP projectors, and those used by three-chip projectors.

Dolby Digital contains five full bandwidth channels and a true LFE (low frequency effects or bass) channel (known as a 5.1 configuration). A standard for high-quality digital audio that is used for the sound portion of video stored in digital format, especially videos stored on DVDs.

An upgrade of Dolby Digital, uses six full bandwidth channels and a true LFE channel to create a more detailed and enveloping sound.

The standard television, laserdisc, satellite, and videotape surround sound format is Dolby Pro Logic (DPL). This analog format system starts with four-channel, encodes it down to two and plays back in a four-channel format. DPL is compatible with two-channel broadcast. With DPL, the front speakers are full bandwidth with 20-20k frequencies while the rear speakers are limited in bandwidth and mono. DPL does not have a true LFE (Low Frequency Effects or bass) channel.

DPL II differs from DPL by giving the rear speakers full bandwidth. It is also able to take stereo and Pro Logic formatted sound and create a sound similar to Dolby Digital. Cable television is compatible with both Dolby Pro Logic and Pro Logic II.

All digital TV display technologies have screens with a fixed number of pixels for displaying images. If a video source has a higher resolution than the screen’s resolution, the TV will automatically downconvert the video signal to fit the screen. Downconversion reduces image detail, but downconverted pictures can still look very sharp. A good example is a 1080i HDTV broadcast displayed on a 720p TV.

(Digital Television) refers to the three types of digital television: Standard Definition Television (SDTV), Enhanced Definition TV (EDTV), and High Definition Television (HDTV).

(Digital Visual Interface) is a standard that defines the digital interface between digital devices such as projectors and personal computers. For devices that support DVI, a digital-to-digital connection can be made that eliminates the conversion to analog and thereby delivers an unblemished image.

(Enhanced Definition Television) refers to picture quality superior than that of NTSC, PAL, or SDTV but is not sharp enough to be considered HD. EDTV uses the 480p (progressive scan) video format. EDTV approximates the high quality of HDTV. To take advantage of the 480p standard, you must use a video source that can output that type of signal.

The Energy Star program was introduced by the EPA (Environmental Protection Agency) in 1992, and set standards for product power consumption in “standby” mode. (When a component is switched off but still plugged into an AC power source, it continues to draw a small amount of power in standby mode to keep circuits active and ready for quick turn-on.)

Provides an on-screen listing of available channels and program data for an extended time period (typically 36 hours or more). Examples of program guides include subscription services like TiVo® and free guides like TV Guide® On Screen.

Electronic device that acts as active filters used to boost or attenuate certain frequencies.

In interlaced-scan video, each complete frame is split into two sequential fields, each of which contains half the picture information. One field contains the odd scanning lines, and the other field the even lines.

Flat panel televisions and displays utilize either Plasma or LCD technology to provide viewers with the ultimate viewing experience. This type of television is generally thin and light enough to mount on a wall or from a ceiling.

The rate at which frames are displayed. The frame rate for movies on film is 24 frames per second (24 fps). Standard NTSC video has a frame rate of 30 fps (actually 60 fields per second). The frame rate of a progressive-scan video format is twice that of an interlaced-scan format. For example, interlaced formats like 480i and 1080i deliver 30 complete frames per second; progressive formats like 480p, 720p and 1080p provide 60.

The range and balance of sound across the audio spectrum. Good sound reproduction requires that all audible frequencies (approx. 20 - 20,000Hz) are reproduced at roughly the same volume, although the highest and lowest octaves are less important.

The most popular halogen lamp in lower cost projectors and overhead projectors. These lamps typically last about 40 hours. For convenience, most projectors using halogen lamps carry a spare as a quick method of going to the backup lamp. Metal halide lamps and UHP lamps are used in most of the medium and higher priced, more powerful portables.

Measures the light-reflecting ability of a projection screen. The higher the number, the greater the amount of light reflected back to the viewer(s).

Ghosting means multiple overlaid TV images or “ghosts” which you can notice around the objects while watching TV. The broadcast signal traveling to your TV through various obstacles, for example hills or tall buildings, causes ghosting and your antenna picks up the original TV signal along with signals reflected by the obstacles. If the ghosting is changing rather than static, it may be caused by the signal reflected by flexible objects, for example trees.

Gauge is a unit used to measure wire thickness. The smaller the number, the thicker the wire. (i.e. 10-gauge wire is much thicker than 16-gauge wire). A change of three in the gauge number tells you that the wire thickness has doubled or halved. Also see: AWG.

A listening term. A sonic analog of the grain seen in photos. A sort of “grittiness” added to the sound.

Means that a display device, such as a plasma display or projector, slowly loses intensity (brightness) as it is used. At the half-life point, the device is half as bright, as it was when it was new.

Harmonic sound energy unintentionally added by an electrical circuit or speaker. It is expressed as a percentage of the original signal.

Also called overtones, these are frequencies that are multiples of the original or “fundamental” frequency. Harmonics extend in frequency beyond the audible range.

(High-Bandwidth Digital Content Protection) is a method for protecting copyrighted digital content. It uses DVI or HDMI to encrypt transmission between a video source (such as a set-top box, DVD player, or computer) and a digital display device (such as a projector, monitor or television). To view digital HDCP protected content, both the sending and receiving device must support HDCP.

(High-Definition Multimedia Interface) first industry-supported uncompressed video and audio standard. HDMI supports, standard, enhanced, high-definition video, plus multi-channel digital audio, and interactive controls on a single cable. It transmits all ATSC (Advanced Television Systems Committee) HDTV standards and supports 8-channel digital audio.

A remote control protocol that is an optional part of the HDMI spec — CEC stands for consumer electronics control. Available from HDMI version 1.2a on, HDMI-CEC allows multiple HDMI-connected components to be operated from a single remote control without any special setup or programming. HDMI-CEC is a two-way communications system, and up to 10 devices can be controlled in a system. Each electronics manufacturer calls this feature something different: Panasonic uses EZ-Sync, Samsung Anynet+, Sony BRAVIA Theatre Sync, Toshiba CE-LINK, LG SimpLink, etc.

(High Definition Television) is digital television system with a higher resolution than the NTSC, PAL, and SECAM formats. HDTV currently consists of the following formats, 720p, 1080i, and 1080p. HDTV possesses at least twice the resolution of standard televisions, allowing for much more detail to be shown compared to analog television or regular DVD. In addition, the technical standards for broadcasting HDTV are also able to handle 16:9 aspect ratio pictures without using letterboxing, thus further increasing the effective resolution for such content.

(High Density DVD or High Definition DVD) is a next-generation optical disc format designed for high-density storage of high-definition video and data. A HD DVD disc can store substantially more data than a standard DVD, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser), which allows more information to be stored digitally in the same amount of physical space. In comparison to Blu-ray, which also uses a blue laser, HD DVD has less information capacity per layer (15 gigabytes instead of 25), though HD DVD is easier and cheaper to manufacture than a Blu-ray pre-recorded disc due to its sharing the same basic disc structure as a standard DVD. The 30 GB dual-sided HD DVDs have been used on nearly every movie released in this format. Blu-ray has only released movies on 25 GB single layer discs.

(High Definition Ready) term often given to a display that can accept and display a HD signal of either 720p, 1080i, or 1080p using component video or digital input. However, the display does not have a built-in HDTV tuner and would require one in order to view HD television.

A measure of frequency, where one Hertz equals one cycle per second. In video, Hertz is used to describe a frame rate in frames per second. For example, you’ll often see 24-frames-per-second video at listed as “24Hz.”

An audio and video system designed to reproduce the theater sound experience at home. Usually consisting of a 5.1 multi-channel surround sound receiver, DVD player; left, right front speakers; a center channel speaker; and two rear surround speakers. Six and Seven channel discrete formats (DTS ES and THX EX, etc) have been recently introduced.

First conceived by Apple Computer (as FireWire), then developed by the IEEE (Institute of Electrical and Electronics Engineers), this high-speed two-way connection allows easy transfer of digital data between consumer electronics gear and computers. Found on some HDTV-capable TVs, tuners, and recorders. Note that some HDTVs equipped with an IEEE 1394 port only permit playback through the connection, not recording.

The total opposition (resistance, capacitance and inductance) offered to the flow of an alternating current. You can think of impedance as resistance (ohms) that can vary at different frequencies.

Single unit containing both a preamplifier and a power amplifier.

Speakers designed to mount flush with the wall and use the wall’s interior air space as its enclosure.

Video systems in which each frame of video consists of two video fields. The odd numbered lines are contained in the first field and the even numbered lines are contained in the second field. When the image is delivered to a video device such as a television, the odd and even fields are delivered at 50 or 60 fields per second and your eye sees an integrated image. LCD and plasma screens cannot display interlaced signals and must first convert them to a progressive format and then they can display the transmitted images.

“Keystoning” is a form of video image distortion that occurs with front projectors if the centerline of the projector’s lens is not perpendicular to the screen. Keystoning results in an image, which is shaped like a trapezoid rather than a rectangle — the top of the picture is wider than the bottom, or the left side is taller than the right, for example. Most front projectors include “keystone correction” to correct this distortion.

(Liquid Crystal Display) is a thin, flat panel display device. LCD displays utilize two sheets of polarizing material with a viscous liquid crystal solution between them. A transistor sends an electric current through the liquid, causing the crystals to align so that light, produced from a lamp behind the screen, gets filtered when passed through them.

A projection TV technology based on LCD. With LCoS, light is reflected from a mirror behind the LCD panel rather than passing through the panel. The control circuitry that switches the pixels on and off is embedded further down in the chip so it doesn’t block the light, which improves brightness and contrast. This multilayered microdisplay design can be used in rear-projection TVs and projectors. TV makers use different names for their LCoS technologies — Sony uses SXRD™, while JVC uses D-ILA™ or HD-ILA™.

An LED is a semiconductor diode that typically emits a single wavelength of light when an electric current passes through it. Different colors can be generated based on the material used; common colors include red, green, blue, and white.
White LEDs are used as backlights in some newer flat-panel LCD TVs, while colored LEDs are used in some recent DLP rear-projection TVs.

Letterbox is a method of preserving the original aspect ratio of a production when it is presented on a projector with a different aspect ratio. This is accomplished by showing the full image and black where no image exists.

Measures the amount of light produced by a video display, and is an especially important spec for projectors. Expressed in “lumens” or “ANSI lumens,” with a higher number indicating greater light output, which results in a brighter picture.

Also know as “low-level,” an audio term referring to the signal before power amplification. In a system with separate pre-amp and power-amp, the pre-amp output is line level. CD players, VCRs, DVD players, laserdisc players etc., are connected in a system at line level, usually with shielded RCA type interconnects.

The unit of measure for light output of a projector. Different manufacturers may rate their projectors’ light output differently. “Peak lumens” is measured by illuminating an area of about 10% of the screen size in the center of the display. This measurement ignores the reduction in brightness at the sides and corners of the screen. The more conservative “ANSI lumens” (American National Standards Institute) specification is made by dividing the screen into 9 blocks, taking a reading in the center of each, and averaging the readings. This number is usually 20-25% lower than the peak lumen measurement.

Maximum Resolution refers to the highest resolution that a given projector can display. If the maximum resolution exceeds the native resolution, the image is usually scaled to match or approximate the native resolution of the projector. Scaling reduces the image resolution and produces some artifacts in the image that are more apparent when viewing text than graphics or video.

Equal to one million Hertz. Video signal bandwidth is typically expressed in megahertz.

These types of lamps are used in many medium and all high end portable projectors. They typically have a half life of 1000-2000 hours. These lamps output a very "hot" temperature light similar to mercury vapor lamps used in streetlights. Their whites are extremely white (with slight bluish cast) and make the whites of halogen lamps appear yellow.

A general term covering several different technologies used in digital rear-projection TVs and projectors. These displays produce large images; the “micro” refers to the postage stamp-sized image chips that create the images. Microdisplay types include DLP, LCD, and LCoS. For a comparison of rear-projection microdisplay types, and details on how each technology works.

Mid frequency bass, usually frequencies just above the sub-bass range, from around 100 - 200Hz or so.

The mid band of an audible signal, typically anywhere between 200Hz and 2kHz. Also refers to the drivers that specialize in these frequencies.

The organization charged with developing video and audio encoding standards. On the video front, consumers are most likely to encounter the MPEG-2 and MPEG-4 compression formats, or “codecs.” These formats are capable of producing very high quality video by employing an adaptive, variable bitrate process that can allocate more bits for complex scenes involving a lot of motion, while reducing the bits in static scenes.
MPEG-2: Used for over-the-air digital television broadcasts, standard DVDs, some Blu-Ray disc and HD DVD discs, and small-dish satellite TV (DIRECTV and Dish).
MPEG-4: This newer format is more efficient than MPEG-2, meaning it can
deliver the same picture quality as MPEG-2 using a lower bitrate. Some Blu-Ray Discs and HD DVDs, and newer DIRECTV and Dish satellite gear use MPEG-4.

An undesirable signal that is unintentionally added to a picture or sound signal.

In home audio there are two main uses of this term: 1. Nominal Power Rating- minimum amount of power recommended for a speaker. 2. Nominal Impedance- theoretically the minimum impedance a speaker will present to the amplifier.

Materials that don’t vibrate much or absorb vibrations, which can affect sound reproduction; materials often included in the construction of a loudspeaker.

(National Television System Committee) is an analog television system that utilizes frames displayed at a rate of 60 half frames (30 full frames) per second. Each frame consists of 484 lines out of a total of 525 (The remaining lines are used for other various information). The NTSC system interlaces its scanlines, drawing odd-numbered scanlines in odd-numbered fields and even-numbered scanlines in even-numbered fields. The NTSC standard is predominately used in Canada, Japan, North Korea, and the United States.

An octave is a doubling or halving of frequency. 20Hz to 40Hz is often considered the bottom octave, 40Hz to 80Hz is the bass octave. 80Hz to 160Hz is the upper bass octave, etc.

The unit used to measure electrical resistance. (The word ohm comes from German physicist Georg Simon ohm, 1787-1854) An 8 ohm loudspeaker presents a good level of resistance and will be compatible with most modern amplifiers.

OLED is an up-and-coming display technology that can be used to create flat-panel TV TVs. An OLED panel employs a series of organic thin films placed between two transparent electrodes. An electric current causes these films to produce a bright light. A thin-film transistor layer contains the circuitry to turn each individual pixel on and off to form an image. The organic process is called electrophosphorescence, which means the display is self-illuminating, requiring no backlight. OLED panels are thinner and lighter than current plasma or LCD HDTVs, and have lower power consumption.

The sound level produced by a loudspeaker.

A condition in which a system is given too high of an input level. A common cause of distortion or product failure.

A digital technique of representing a waveform with more bits of information than would theoretically be needed. Oversampling is used to reduce the amount of noise (unintended information) in a signal.

Over-the-air broadcast is also called terrestrial broadcast. It is standard over-the-air broadcast to an antenna, as opposed to satellite or cable transmission.

(Phase Alternating Line) is an analog television system that utilizes frames displayed at a rate of 50 half frames (25 full frames) per second. Each frame consists of 576 lines out of a total 625 (The remaining lines are used for other various information). The PAL standard is used predominately through-out Europe.

The process of transferring a widescreen movie or other source material to videocassette, DVD, or broadcast so that it fits the squarish 4:3 aspect ratio of most old-fashioned TVs. This results in a significant amount of lost picture information, particularly in the width of the image. Most new HDTVs use the wider 16:9 aspect ratio, which can display all or most of the original picture of widescreen material

Device neither having nor requiring power.

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

The recommended highest power capacity of an amplifier or speaker.

In audio, phase refers to the timing relationship of two or more waves. It’s especially important to be sure that your speakers are wired “in phase.” This means that the drivers of your speakers are moving in and out at the same time. If your speakers are “out of phase” there will be significantly less bass, and a loss of stereo imaging.

Is another commonly used term for an RCA-type plug.

Noise that has equal energy in each octave.

The pillar-box effect occurs in widescreen 16:9 video displays when vertical black bars are placed at the sides of a non-widescreen 4:3 image. The smaller the size of the pixels in an image, the greater the resolution.

Picture-in-picture allows you to create a second viewing window on your television screen enabling you to watch multiple broadcasts simultaneously.

Pixel comes from the words “picture element” and refers to the smallest element in a television picture. Pixels are single displayable video dots from which the overall picture is made up.

The amount of time it takes for a single pixel in a video display to switch from active to non-active; it is measured in milliseconds (ms). If a display’s response time is too slow, faint motion trails may be visible following fast-moving on-screen objects. Pixel response time is an important performance spec for all types of digital flat-panel and projection displays although it’s rarely listed for non-LCD TVs.

Plasma technology is one of the methods used to create flat-panel TVs. The display consists of two transparent glass panels with a thin layer of pixels sandwiched in between (think of this layer as containing somewhere between 800,000 and two million tiny fluorescent bulbs — the pixels). Each pixel is composed of three gas-filled cells or sub-pixels (one each for the red, green and blue primary colors). A grid of tiny electrodes applies an electric current to the individual cells, causing the gas to ionize. This ionized gas (plasma) emits high-frequency UV rays, which stimulate the cells’ phosphors, causing them to glow, which creates the TV image. Plasma displays offer excellent resolution and color and they are the most suitable for the home theatre.

Poly-Si is a popular LCD technology for high-end LCD projectors. Monochrome Poly-Si LCDs are typically placed in each of the three-color light paths inside a projector (one each for red, green and blue). This results in increased color saturation with contrast ratios above 200:1. Poly-Si technology is also a bit faster than the Active Matrix TFT.

A preamp is the control center of an audio/video system. Source component switching is done here, as well as volume and balance control. This component generally has some degree of signal amplification associated with it. AV receivers contain both a preamp and amplifier.

Progressive scanning refers to the smooth picture that appears when the signal is 720 or 1080. Horizontal lines are scanned progressively or in succession in a vertical frame that is repeated 30 times a second.

(Quantum Extended Graphics Array) 2048 x 1536, a resolution that supports up to 3,145,728 pixels.

(Quadrature Amplitude Modulation) a format by which digital cable channels are encoded and transmitted via cable. It allows a direct reception of digital cable channels without the use of an external box. QAM tuners can be likened to the cable equivalent of the ATSC tuner.

Standard pin plug or jack used to connect audio and video components, developed by RCA Laboratories. Also known as a phono plug or jack, even when applied to non-phono equipment.

A loudspeaker that is located beside or behind the listener in a surround sound system.

Rear projection TV systems project the picture against a mirror inside the TV cabinet and you can watch it as you would an average television.

An audio (and/or video) component that combines a pre-amplifier, amplifier(s) and tuner in one chassis. A home theater receiver will also contain multi-channel surround decoders, such as Dolby Digital and DTS.

The digital display technologies (LCD, plasma, DLP, LCoS, etc.) that have replaced picture tubes are progressive scan by nature, displaying 60 video frames per second — often referred to as “60Hz.” HDTVs with 120Hz refresh rate double the standard rate to 120 frames per second by inserting either additional video frames or black frames. Because each video frame appears for only half the normal amount of time, on-screen motion looks smoother and more fluid, with less smearing. It’s especially noticeable viewing fast-action sports and video games.

Resolution reflects the density of lines, and dots per line, which make up a visual image. The number of pixels displayed measures it. The level of resolution directly affects picture quality. Usually the higher number of lines and dots means sharper and more detailed picture.

Sometimes referred to as a “75-ohm coaxial” connection, this kind of jack is commonly used for bringing signals from antennas and other sources outside the home to components with some type of tuner, such as cable boxes, HDTV tuners, VCRs, satellite receivers, TVs, etc. A 75-ohm coaxial cable can carry video and stereo audio information simultaneously.

(Red Green Blue) a type of video standard that consists of three separate signals (red, green, and blue). RGB video is commonly used by computers and with computer monitors. RGB input is often referred to as computer input; RGB output is often referred to as computer output.

Signal to Noise Ratio. An audio measurement of the residual noise of a unit, stated as the ratio of signal level (or power) to noise level (or power), normally expressed in decibels.

A small loudspeaker designed to fit more easily into the interior decor of a home. Typically they need to be used with a subwoofer.

Circuitry that converts a video signal to a resolution other than its original format. Scaling can involve upconversion or downconversion, and may also include a conversion between interlaced- and progressive-scan formats. A scaler can be built into a TV, HDTV tuner, DVD player, or home theater receiver, or may be a standalone component.

On CRT-based TVs, the number of scanning lines measures the screen’s resolution. Scanning refers to an electron gun tracing horizontal lines across a phosphor-coated screen, painting each video frame as a series of lines. Although you may still hear the term “scan lines” used when describing digital TVs that use plasma, LCD, or other pixel-based technologies, it’s not really accurate. These newer TV types flash each complete screen image simultaneously without any type of actual scanning.

The loudness of a speaker at a given voltage. Usually measured at 2.83V, at one meter straight in front of the speaker and excluding reflected energy.

(Standard Definition Television) refers to television systems that have resolutions that meet DTV standards, but are not considered high definition. SDTV is typically a 480i (interlaced) signal. Digital cable and digital satellite programming is widely available in SDTV format. While SDTV does not reach near the quality of HDTV, it is superior over traditional analog television.

Is an analog television system that utilizes frames displayed at a rate of 50 half frames (25 full frames) per second. Each frame consists of 576 lines out of a total 625 (The remaining lines are used for other various information). The SECAM television standard is used by France, Eastern Europe, Russia and several nations in Africa. Although similarities exist between the two, the SECAM color component is implemented differently than PAL color component. SECAM has a higher resolution than NTSC.

How much relevant content (signal) something has compared to non-relevant content (noise); expressed in decibels.

A pure, single frequency wave. Audio signals are sine waves or combinations of sine waves.

Derived from the Greek word meaning solid. A two-channel audio format designed to provide the illusion of a three-dimensional, holographic image between the speakers.

Set-top box is responsible for receiving, converting and sending the picture and sound of the broadcast to the associated television. An example would be either a cable or satellite box.

A speaker designed to specialize in low-frequency reproduction. A true subwoofer should be able to at least reach into the bottom octave (20-40Hz). Although any location will result in bass that appears to come from the satellite speakers, they usually sound best when placed near the front speakers.The human ear can barely hear many of the low frequencies projected by a subwoofer, yet its frequencies can be felt. Many modern day filmmakers depend on LFE (Low Frequency Effects) to heighten the tension or drama.

The multichannel format developed by the Moving Picture Experts. It refers to the five discrete, full bandwidth (20-20kHz) channels - left, right, and center fronts, plus left and right surrounds - and the “.1” refers to the limited bandwidth (20-120Hz) subwoofer channel.

(Super Video Graphics Array) 800 x 600, a resolution that supports up to 480,000 pixels.

(Super Extended Graphics Array) 1280 x 1024, a resolution that supports up to 1,310,720 pixels.

Found on nearly all of the TVs we sell, this four-pin connector usually provides a sharp, clear picture by transmitting the chrominance and luminance portions of a video signal separately. The signals can then be processed separately, reducing interference. Direct s-video connections generally outperform composite connections when hooking up video components like DVD players, DBS receivers, and S-VHS and Hi8 recorders and camcorders. S-Video is a video transmission standard that uses a 4-pin mini-DIN connector to send video information on two signal wires called luminance (brightness, Y) and chrominance (color, C). S-Video is also referred to as Y/C.

(Thin Film Transistor) a type of LCD flat-panel display screen. Since each pixel is controlled by individual transistors, crosstalk between pixels is reduced which improves image stability. TFT screens provide the best resolution of all the flat-panel techniques and it is also the most expensive. TFT screens are sometimes referred to as active-matrix LCDs.

An acronym for Tomlinson Holman Experiment, THX is a set of technical standards and performance criteria developed by Lucasfilm to ensure that moviegoers see and hear a film at optimum performance levels, “as the director intended.” This comprehensive set of standards includes rigorous specifications designed to optimize equipment, room acoustics, background noise levels, and projection and viewing angles.

THX certification designed for optimal performance in smaller listening environments and at lower volume levels; conceived for rooms of less than 2000 cubic feet.

A home theatre surround format engaging an additional rear surround speaker, allowing for dramatic 360º surround sound. This technology made it’s theatrical debut with the opening of Star Wars: Episode I The Phantom Menace.

THX certification designated for ultra high-end A/V gear, as opposed to THX Select, which is aimed at more moderately priced equipment; conceived for rooms of more than 2000 cubic feet.

It refers to another term for “optical audio cable. Originally implemented and developed by Toshiba.

The ability of a speaker to respond to any sudden change in the signal without smearing or blurring the sound. A speaker that can react quickly to rapid changes in sound has “good transient response.”

High audio frequencies, the upper end of the audio spectrum, usually reproduced by tweeters, – about 2kHz and up.

a universal remote allows you to combine all your remotes into one. All universal remotes are either pre-programmed with codes from the factory or permit you to program codes into the remote. Remember to select a remote with enough programmability and memory for all its necessary functions.

The term used to describe the conversion of a lower resolution to an apparently higher one. This process increases the number of pixels and/or frame rate and/or scanning format used to represent an image by interpolating existing pixels to create new ones at closer spacing.

(Ultra Extended Graphics Array) 1600 x 1200, a resolution that supports up to 1,920,000 pixels.

An electronic blocking device that can control programming to prevent viewing of questionable content. Programs can be screened according to age and content-based ratings through the easy-to-use on screen display.

(Video Graphics Array) 640 x 480, a resolution that supports up to 307,200 pixels.

Measures a video display’s maximum usable viewing range from the center of the screen, with 180° being the theoretical maximum. Most often, the horizontal (side to side) viewing angle is listed, but sometimes both horizontal and vertical viewing angles are provided. For most home theater setups, the horizontal viewing angle is more critical.

A unit of electrical power. A watt of electrical power is the use of one joule of energy per second. Watts of electrical power equals volts times amperes.

A full audio spectrum signal with the same energy level at all frequencies. White noise has much more treble energy than pink noise.

(Wireless Fidelity) a standard based on 802.11 protocol for wireless local area networks (WLAN). It was developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). There are four specifications in the family: 802.11, 802.11a, 802.11b, and 802.11g. All four use the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance) for path sharing.

An IEEE specification for wireless networking that operates in the 5 GHz frequency range (5.725 GHz to 5.850 GHz) with a maximum 54 Mbps data transfer rate. The 5 GHz frequency band is not as crowded as the 2.4 GHz frequency because the 802.11a specification offers more radio channels than the 802.11b. These additional channels can help avoid radio and microwave interference.

Is the international standard for wireless networking that operates in the 2.4 GHz frequency range (2.4 GHz to 2.4835 GHz) and provides a through out of up to 11 Mbps. This is a very commonly used frequency. Microwave ovens, cordless phones, Bluetooth devices and medical and scientific equipment all work within the 2.4 GHz frequency band.

A new higher speed standard called 802.11g features complete backwards compatibility with 802.11b but it boosts the network speed to 54 Mbps.

Widescreen refers to a television or display panel using a 16:9 aspect ratio. 16:9 is the aspect ratio of movie screen and widescreen DTV formats used in all HDTV (High Definition TV) and some SDTV (Standard Definition TV).

A technique originally invented by Hewlett-Packard for its ink jet printers. Texas Instruments, developer of DLP display technology, employs wobulation in some of its image chips used in rear-projection TVs. Like interlacing, wobulation shows half the picture at a time, but displays the two halves so rapidly that our eyes combine the two parts into one. A 1080p DLP TV can display images with 1920 x 1080 pixels, yet its DMD (Digital Micromirror Device) image chip has 960 x 1080 mirrors. Half the image is displayed, then a separate pivoting reflective panel called an “actuator” shifts the display a half pixel’s width to the side. This all happens fast enough to generate 60 full frames per second, for a clean progressive-scan image. Texas Instruments calls this technique SmoothPicture™, and it is also often referred to as “pixel-shifting.”

A loudspeaker dedicated to producing low frequency sound.

(Wide Super Extended Graphics Array) 1920 x 1080, a resolution that supports up to 2,073,600 pixels.

(Wide Ultra Extended Graphics Array) 1920 x 1200, a resolution that supports approximately 2,304,000 pixels with a native 16:10 aspect ratio.

(Wide Video Graphics Array) (apx.) 854 x (apx.) 480, a resolution that supports approximately 400,000 pixels.

(Wide Extended Graphics Array) term used to describe several resolutions including; 1280 x 720, 1280 x 768, 1365 x 768, and 1024 x 1024.

(Extended Graphics Array) 1024 x 768, a resolution that supports up to 786,432 pixels.

The zoom lens ratio is the ratio between the smallest and largest image that a lens can project from a fixed distance. For example, a 1.4:1 zoom lens ratio means that a ten-foot image without zoom would be a 14-foot image with full zoom. Conversely, a ten-foot diagonal image at 15 feet with no zoom would still be a ten image at 21 feet at maximum zoom (15 x 1.4 = 21 feet).