1080i: the resolution of the picture is 1920 vertical pixels by 1080 horizontal pixels, "i" stands for interlaced scanning. Interlaced scanning is based on the principle that the screen shows every odd line at one scan of the screen and then all the even lines in a second scan.
1080p: Full HD. The resolution of the picture is 1,920 vertical pixels by 1,080 horizontal pixels, "p" stands again for progressive scanning. This format works on the same principle as 720p; the only difference is that in this type there are more pixels and the resolution is better.
16:9 is the aspect ratio of typical home movie theater screens as well as all flat-panel displays currently sold for consumer use. It stands for 16 units of width for every 9 units of height.
4:3 is the aspect ratio of traditional National Television Systems Committee (NTSC) TV screens; it stands for four units of width for every three units of height.
5.1 Surround Sound System: A surround sound system that consists of front speakers (left, center, and right), rear speakers (right and left), and a subwoofer. This is also the audio standard for digital TV and HDTV.
6.1 Surround Sound System: A surround sound system that consists of front speakers (left, center, and right), rear speakers (left, center, and right), and a subwoofer powered by a dedicated amplifier.
720p: the resolution of the picture is 1,280 vertical pixels by 720 horizontal pixels and p stands for progressive scanning. Progressive scanning offers a smoother picture as 720 horizontal lines are scanned progressively or in succession in a vertical frame that is repeated 30 times a second.
75-Ohm Cable: Primarily RG59/U or RG6/U coaxial cable used to carry modulated audio and video signals over one cable. RG6/U is recommended for highest quality coaxial cable performance and to future proof installations. RG6/U is a must for DSS satellite installations.
A
AC-3: The original named used for Dolby Digital, it stood for Audio Coding Version 3. The name was later changed to feature the Dolby name.
Active Crossover: A powered electronic network that divides up the frequency constituents of an audio signal (bass, midrange, and treble) before it is amplified and sent to the various drivers in a speaker system. While active crossovers are often contained within sub-woofer enclosures along with the bass driver(s), those that work with multi-way systems may also be outboard mounted.
Amplifier: A component that increases the gain or level of an audio signal.
AM: Amplitude modulation.
Aspect ratio: The ratio between the width and height of the TV picture on the screen. In a normal TV set or monitor the aspect ratio is 4 to 3 (4:3). The new aspect ratio in HDTV and IDTV/EDTV* is 16:9 which resembles the aspect ratio in a movie theatre (Widescreen). New TV systems support both 4:3 and 16:9 aspect ratio [[PAL]] PLUS*) and can automatically switch between them.
ATSC: Advanced Television Systems Committee. Group responsible for the new digital television standards. See DTV.
A/V Receiver: Also called a Home Theater receiver, sometimes the term "integrated" is also used. Receivers take audio signals from components such as a CD player, tape deck and phonograph, amplify it and output it to the speakers. An A/V receiver is designed to also accept video inputs, such as from a DVD player, cable box or satellite receiver, and output the signal to a television. In most cases the video signal is not processed but simply passed through to the TV. A/V receivers, in most cases, also have Dolby and DTS decoders to play multi-channel audio.
A/V Inputs: The connections on any component, such as a TV, receiver or DVD recorder that enable connection to other output devices. The inputs often take the form of RCA jacks.
AVI: stands for Audio Video Interleave. This is a container video format that specifies certain structure how the audio and video streams should be stored within the file. AVI itself doesn't specify how it should be encoded (just like the streaming format ASF), so the audio/video can be stored in various ways.
B
Baffle: In speaker design, a baffle is most commonly a planar surface on which the individual drivers are mounted. They are often used inside the cabinet to accomplish specific acoustic objectives.
Bass: Low frequencies; those below approximately 200 Hz
Blu-ray: is a name for a optical disc standard which uses blue-violet laser instead of red laser used in CDs and in DVDs. This allows manufacturers to store more data using the same amount of disc surface. In fact, Blu-ray got its name from the technology, basically the "Blu" is from blue-violet diode and the "ray" is from optical ray. The "e" was intentionally dropped so that the full term "Blu-ray" could be registered as a trademark.
Bridging: Combining two channels of an amplifier to make one channel that's more powerful. One channel amplifies the positive portion of an audio signal and the other channel amplifies the negative portion, which are then combined at the output.
C
CEA: The Consumer Electronics Association. An association of manufacturers of consumer electronics products.
Center Channel: The center speaker in a home theater setup. Ideally placed within one or two feet above or below the horizontal plane of the left and right speakers and above or below the display device, unless placed behind a perforated screen. Placement is important, as voices and many effects in a multichannel mix come from this speaker.
CES: The International Consumer Electronics Show (CES) is a non-public trade show held each January in Las Vegas, Nevada. It is sponsored by the Consumer Electronics Association (CEA). This is the largest tradeshow in the world for all things electronic, where many new products are introduced, or new products are announced. The show is held at the Las Vegas Convention Center with additional venues (The Venetian, Hilton, and the Sands Expo and Convention Center, etc.) used for certain specialties.
Channel: In components and systems, a channel is a separate signal path. A four-channel amplifier has at least four separate inputs and four separate outputs.
Class A: A type of amplifier design where the output device is always on for both parts of a complete sinusoidal cycle. Class A is the most inefficient of all power amplifier designs, averaging only around 20%. Because of this, Class A amplifiers are large, heavy and run very hot, due to the amplifier constantly operating at full power. The positive effect is that class A designs are inherently the most linear, producing the least amount of distortion and are thus often found in high-end audio equipment.
Class B: is opposite to class A in that the current in a specific output flows for one half cycle. In other words, both output devices are never on simultaneously. This system allows for much better efficiency, but displays poor linearity around the crossover region, since it takes time to turn one device off and the other device on. This in turn translates into extreme crossover distortion, thus restricting class B designs to power consumption critical (battery operated) applications, such as two-way radio and other communications audio.
Class AB: is a combination of both class A and B in that the output bias is set so that current flows in a specific output device appreciably more than a half cycle but less than the entire cycle. That is, only a small amount of current is allowed to flow through both devices, unlike the complete load current of class A designs, but enough to keep each device operating so they respond instantly to input voltage demands. Thus the non-linearity of class B designs is eliminated, without the inefficiencies of the class A design.
CLV (Constant Linear Velocity): Method of spinning a disc, in a CD-DA or Laserdisc drive, in which the spin speed of the disc is regulated as the drive's head mechanism moves towards the outside edge of the disc. This way, the data rate is maintained across the entire surface of the disc.
Coaxial Cable: The standard cable consisting of a central inner conductor and a cylindrical outer conductor. Used for many video connections, especially by Cable TV companies.
Component Video: Analog video inputs that split the video signal between up to three cables. Video information is either sent in RGB or YPbPr signals. Component video can carry progressive scan and high definition signals.
Composite Video: An analog video input where the video signal is carried on a single cable. It cannot carry high definition or progressive scan signals.
Crosstalk: The interference between two or more audio or video signals caused by unwanted stray signals. In audio, crosstalk exhibits itself as signal leakage, typically between left and right channels or between different inputs, or as noise.
Crossover: A component that divides an audio signal into two or more ranges by frequency, sending, for example, low frequencies to one output and high frequencies to another. An active crossover is powered and divides the line-level audio signal prior to amplification. A passive crossover uses no external power supply and may be used either at line level or, more commonly, at speaker level to divide the signal after amplification and send the low frequencies to the woofer and the high frequencies to the tweeter.
Crossover Frequency: The frequency at which an audio signal is divided. 80 Hz is a typical subwoofer crossover point and is the recommended crossover point in theatrical and home THX systems. Frequencies below 80 Hz are sent to the subwoofer; signals above 80 Hz are sent to the main speakers.
Crossover Slope: The rate of attenuation expressed in decibels of change for every octave away from the crossover frequency.
D
Decibel: Used commonly for measuring volume. Decibels represents the magnitude of a physical quantity relative to a reference level. Its not just used for sound (light intensity is one alternative). A decibel is more simply the pressure of the sound you're listening to. The higher the decibel, the higher the pressure. Not all sound is essentially louder at higher decibels, however, because there are many frequencies of sound. The human ear reacts differently to each frequency, so sometimes a sound at very high decibel won't actually sound as loud as expected.
Diffusion: In terms of audio, the scattering of sound waves that makes it difficult to tell which direction the sound is coming from.
Dispersion: The spreading of sound over a wide area.
DLP: Digital Light Processing. A Texas Instruments process of projecting video images using a light source reflecting off of an array of tens of thousands of microscopic mirrors. Each mirror represents a pixel and reflects light toward the lens for white and away from it for black, modulating in between for various shades of gray. Three-chip versions use separate arrays for the red, green, and blue colors. Single-chip arrays use a color-filter wheel that alternates each filter color in front of the mirror array at appropriate intervals.
DOLBY: A compression/expansion (companding) noise reduction system developed by Ray Dolby, widely used in consumer, professional and broadcast audio applications. Signal-to-noise ratio improvement is accomplished by processing a signal before recording and reverse-processing the signal upon playback.
DOLBY DIGITAL: A multi-channel audio format that allows 1 to 7.1 channels of sound for playback on equipment with a Dolby Digital-compatible decoder. This lossy audio compression format is common in movie theaters, standard on DVD-Video discs and will be used in future HDTV broadcasts. Fortunately, even in the absence of a proper decoder, all DVD-Video players will "downmix" the signal into two-channel surround. (See also DTS)
DTS (Digital Theater Systems): A competing multi-channel audio format that encodes 1 to 7.1 channels of sound for playback on equipment with a DTS-compatible decoder. This lossy audio compression format is common in movie theaters, on some DVD-Video discs and laserdiscs. (See also DOLBY DIGITAL)
DTV: Acronym for Digital Television. See ATSC, HDTV.
DVD: stands for Digital Versatile Disc. It is very often used as a replacement acronym for DVD-Video, which is one standard based on DVD format.
DVI Cable: Digital Visual Interface. DVI is designed to support uncompressed digital video data and high definition. Many high definition TVs use DVI and most new computers and video cards use DVI to connect to a monitor.
E
Enclosure: An acoustically designed housing or structure for a speaker.
Equalization: The attempt to reproduce a desired frequency response through the use of graphic equalizers or tone controls.
Equalizer: A device used in audio systems to provide more detailed control of the system's frequency response. Electrically inserted between the pre- and power-amp stages, an equalizer typically divides the frequency range into 15 or 32 bands and allows each to be increased or decreased. It's easy to think of an equalizer as a very fancy tone control.
F
FM: Frequency Modulation, the system used for FM radio broadcasts. FM Radio has much better clarity than AM Radio.
Frequency Response: Reproduction range of an audio component. A speaker with a frequency response of 50-22,000 Hz is capable of reproducing bass notes of 50 Hz all the way up to supersonic frequencies above 20,000 Hz. See Frequency Response (+/-).
Frequency Response (+/-): Most frequency response specifications have a +/- dB number with them, for example +/- 3 dB. The +/- 3 dB is the variance throughout the specified range. For example, a component that reproduces sound from 20-20,000 Hz +/- 3 dB will vary no more than +1.5 dB or - 1.5 dB throughout the 20-20,000 Hz range. Smaller numbers are better as they mean more accuracy. Most electronic components such as CD players and amplifiers have small +/- numbers; speakers are usually rated +/- 3 or +/- 4 dB. This reflects how much more difficult it is to create sound with a speaker vs. modify or amplify a signal with an electronics component.
Full HD: 1080p picture
G
Gain: The volume/amplification level of an audio or video signal.
Graphic Equalizer: A type of audio equalizer which uses a graphical layout to represent the changes made to various frequencies.
H
HD: High Definition
HDMI: High Definition Multimedia Interface, a single digital connection that transfers both audio and video information. HDMI has become the default digital connection for HDTVs, cable and satellite boxes, video processors, Blu-ray players, upconverting DVD players, and HD DVD players. Audio components such as receivers now use HDMI, as well, though it is less common use than in video components.
HDTV: High Definition Television, part of the ATSC standard. To be considered high definition, a TV must support a resolution of either 720p, 1080i, or 1080p. (Many HDTVs are 768p, but no content is broadcast or recorded at this resolution.) See ATSC and DTV.
Horn: A type of speaker that looks like a horn. These speakers have small drivers and very large mouths; the horn shape serves to transform the small radiating area of the driver into the much larger radiating area of the mouth of the horn.
I
IMAX: Super-large film format traditionally printed on 70mm stock and projected onto screens in the region of 22 x 16m in size; created by IMAX Corporation of Canada and now also in digital format.
Impedance: A measure of the impediment to the flow of alternating current, measured in ohms at a given frequency. Larger numbers mean higher resistance to current flow.
Integrated Amplifier: A combination preamp and amplifier.
Interconnects: Any cable or wire running between two pieces of A/V equipment. For example, RCA terminated cables connecting pre/pros and amps.
Interlaced: Interlacing is done to improve image quality by removing the flicker in-between frames. It is used to prevent consuming extra bandwidth in the video signal. The principle is that every other frame includes opposite lines of resolution. That means that one frame will contain half the lines of resolution in an image (every other line) and the next frame will have the missing lines. This method makes the image look fluid and smooth to the human eye, but if slowed down, you could see that you're actually looking at half a frame at a time. Most standard definition TVs use interlacing while LCD, DLP, and plasma displays cannot be interlaced due to their design. They use progressive scan instead.
J
Just move along... nothing to see here
K
Kiwi: A flightless bird that is native to New Zealand. Also, our Mascot.
L
LASERDISC:
12" consumer optical disc format used for the storage of audio and video signals. The laserdisc utilizes a high quality analog video signal capable of >400 lines of horizontal resolution as well as analog and/or digital audio tracks. The laserdisc has all but been replaced by the all digital DVD format.
LCD: Liquid Crystal Display. A screen for displaying text and graphics based on liquid crystal technology, where minute currents change the transparency of the screen. The advantages of LCD screens are: very low power consumption (can easily be battery driven) and low price of mass-produced units. The LCD system first became wide spread in digital wristwatches which can operate for a very long time on small batteries. The disadvantages were: narrow-viewing angles, slow response (the first ones were too slow to be used for video), invisibility in the dark unless the display is backlit, and difficulties in displaying true colors on color LCD displays. With the introduction of new technology and especially TFT* driven LCD displays, picture quality resembles the quality of a CRT the Cathode Ray Tube used in televisions and monitors). Brightness has improved dramatically and the price is dropping constantly.
LED:
Light Emitting Diode
Low-Pass Filter: A circuit that allows low frequencies to pass but rolls off the high frequencies. Most subwoofers have low-pass filters built in and many surround sound decoders have subwoofer outputs that have been low-pass filtered.
M
Midrange: The middle of the audio frequency range. Also used as a term for loudspeaker drivers designed to reproduce this range.
Motion Blur: Motion blur is a phenomenon specific to LCD panels, it occurs when the response time and refresh rate of the TV cannot keep up with motion on the screen which can trails to appear behind fast moving objects.
Multimedia: A somewhat ambiguous term that describes the ability to combine audio, video and other information with graphics, control, storage and other features of computer-based systems. Applications include presentation, editing, interactive learning, games and conferencing.
Multi-source: A system with multiple sources. Can also be used to describe a receiver that can provide multiple different sources into different rooms.
Multi-room: A system that provides audio or video to multiple areas. Usually with only one source.
Multi-zone: A system that provides different sources into multiple areas simultaneously.
N
Noise: A general term used in electronics to indicate any unwanted electrical signal, unrelated to the original signal. In audio, noise is generally manifested as hiss and static.
NTSC: National Television Standards Commission. Video/broadcast standard used in the USA, Canada, Japan, Mexico, and other countries. Delivers 525 horizontal lines of resolution at 30 fps (frames per second).
O
Ohm: A measure of how much something resists (impedes) the flow of electricity. Larger numbers mean more resistance.
OLED: Organic Light-Emitting Diode.
P
PAL (Phase Alternate Line): Color TV broadcasting standard used mainly in Western Europe, Australia, most of Asia, and parts of South America and Africa, featuring 625 lines per frame and 50 frames per second.
Plasma: An emissive flat-screen technology in which ionized gas is sandwiched between panels of glass that are embedded with wire. These displays are slim (about 4 inches deep) and can be created in sizes as large as 60 inches diagonally; they are generally used in flat-panel TVs.
Power Amp: See Amplifier.
Power Output: A measure, usually in watts, of how much energy is modulated by a component.
Preamplifier: A control and switching component that may include equalization functions. The preamp comes in the signal chain before the amplifiers.
Progressive Scanning: Each frame of a video image is scanned complete, from top to bottom, not interlaced. For example, 480p means that each image frame is made of 480 horizontal lines drawn vertically. Computer images are all progressively scanned. Requires more bandwidth (twice as much vertical information) and a faster horizontal scan frequency than interlaced images of the same resolution.
Q
Quit looking... it's not nice to stare.
R
RCA Jacks: Coaxial connections used in audio and video components, most commonly used to transmit analog signals. (An exception is coaxial digital audio connections.) Some examples of the use of RCA jacks is for component video, stereo analog audio, and composite video. RCA jacks and connection cables were by far the most commonly used connections when audio and video were solely analog, and are still in widespread use today. Although, HDMI standard is overtaking the RCA format.
Receiver (A/V): A receiver that incorporates surround sound processing and additional amplifier channels to drive center and surround speakers. Most A/V receivers also include video switching.
Refresh Rate: The number of times the screen is redrawn per second, represented as Hertz.
RGB: Red, Green and Blue. The primary colors of video.
Resolution: The number of pixels on the screen, often expressed as width x height or number of vertical lines of resolution. 1920x1080 or 1080p are the same, the screen has 2,073,600 individual pixels.
Response Time: This specification represents the amount of time it takes for one pixel to go from active (black) to inactive (white) and back to black again. Applies only to LCD panels.
S
S-Video: A video signal that carries luminance (Y, brightness) and chrominance (C, color) values as physically separate signals. Also known as Y/C video. Usually uses a small four-pin mini-DIN connector.
Sound projector: A bar-like enclosure with several--sometimes dozens--of drivers that produce a surround sound experience. By digitally focusing the sound and controlling the delay of each driver, the listener perceives the sound coming from different points in the environment.
Soundbar: See Sound projector.
Stylus: A small diamond on the end of a cartridge's cantilever. This sits within the groove of an LP and picks up the vibrations recorded therein. The stylus is generally spherical or elliptical in shape, although some variations have been developed, all with a view to more accurately tracking the groove while reducing damage to it. Elliptical styli are only suitable for tracking weights of less than around two grams because their low contact area with the groove can cause damage.
Subwoofer: A subwoofer is an individual speaker commonly found in home theater sound systems that processes bass sounds as low as 15 hertz.
Surround Speakers: The distribution of sound resulting from digital decoding. Maybe 5.1, which is front speakers (right and left), rear speakers (right and left), center channel speaker, and a powered subwoofer. May be 6.1, which is front speakers (right and left), front center channel speaker, rear speakers (right and left), rear center channel speaker, and a powered subwoofer.
T
THX: THX stands for Tomlinson Holman's eXperiment. THX is a quality assurance standard. To be a THX certified a television must meet certain standards of predictable reproduction of film source content.
THX was created in 2001 by Lucasfilm Ltd.
Timbre: The quality of a sound that distinguishes it from other sounds of the same pitch and volume. The distinctive tone of an instrument or a singing voice.
Transducer: Any device that converts one form of energy into another form of energy, specifically when one of the quantities is electrical. Thus, a loudspeaker converts electrical impulses into sound (mechanical impulses), a microphone converts sound into electrical impulses, a solar cell converts light into electricity, etc.
Treble: The audible frequencies typically constituted by frequencies above about 5,000 Hertz, although the dividing line between midrange and treble is one of opinion. The human ear is less sensitive to treble than to midrange frequencies.
Tweeter: A speaker driver designed to reproduce high frequencies; usually those over approximately 5,000 to 10,000 Hz. A single loudspeaker design cannot easily handle the full range of human sound (20 Hz to 20 KHz) due to physical constraints. To solve this problem what is called a loudspeaker has (at least) two separate loudspeakers. One for the high frequencies (normally 2 KHz to 20 KHz) called a tweeter. One for the lower frequencies (20 Hz - 2 KHz) called a woofer.
U
UL: Underwriter's Laboratory, a listing service for electrical and electronic equipment.
Universal Remote Control: Simplifies operation by also controlling many brands of TVs, VCRs, DVD players and A/V receivers from one remote control device. (not all are compatible with all brands and models.)
Upscaling: Upscaling involes the use of a video scaler (sometimes found in high definition TVs and certain DVD players). An algorithm is used to convert the resolution of a signal to the resolution desired. For instance, an HD DVD player upconverts regular DVDs (480p resolution) to 1080i resolution, resulting in higher quality. Scalers don't always improve image quality; sometimes, they are necessary to just display the content you're trying to watch. This is especially true with high definition TVs. They must scale standard definition broadcasts to a higher resolution so you can watch them on a high def TV. The quality isn't improved (in fact, it is pretty terrible), but without the scaling, it would be unwatchable.
V
Vacuum Tube: A multi-electrode valve which controls the flow of electrons in a vacuum from electrode to electrode.
W
Watt: A unit of power. One horsepower is equal to 745.7 watts.
Woofer: A single loudspeaker design cannot easily handle the full range of human sound (20 Hz to 20 KHz) due to physical constraints. To solve this problem what is called a loudspeaker has (at least) two separate loudspeakers. One for the high frequencies (normally 2 KHz to 20 KHz) called a tweeter. One for the lower frequencies (20 Hz - 2 KHz) called a woofer. When sound arrives at the loudspeaker it is filtered (separated) into the two (or more) frequency ranges. Because it deals with lower frequencies the woofer is named for the low pitched (low frequency) growl or woof sounds made by dogs. The Bass volume control on a sound system typically controls the woofer. When sound frequency ranges are measured in decades (as opposed to octaves) the woofer normally reproduces the 1st and 2nd decade. In some high end systems a subwoofer has been introduced to handle the very low range 20 Hz to 100/120 Hz (corresponding roughly to the 1st decade) yet others add a mid-range (a.k.a. squawker) speaker to handle the range 300 Hz to 2/3 Khz (roughly corresponding to the 2nd descade) while the woofer handles only the 1st decade frequencies.
X
XLR: A type of connector used for balanced lines. Used for microphones, balanced audio components and the AES/EBU digital connection.
XM Satellite Radio: Subscription satellite radio service sold throughout North America with over 170 stations.
Y
You keep staring, but there's nothing here.
Z
Zone: One or more rooms powered by one or more amplifiers, which are all fed by one source. A home can be divided into multiple zones, which can play multiple sources, even though several rooms (say, the kitchen, dining room, and living room) all play the same source.
A/V Receivers
Amplifiers
