Home Audio Glossary
Researching or shopping for home audio products is easier when you're familiar with the vocabulary. Here's a glossary of some of the most frequently used terms you'll encounter.
5.1 channel surround sound
A movie recording technique that, when paired with a 5.1-channel home theater surround speaker system, surrounds the viewer with sounds from five different speakers for full range sound, and one speaker for low frequency effects.
6.1 channel surround sound
A movie recording technique that, when paired with a 6.1-channel home theater surround speaker system, surrounds the viewer with sounds from six different speakers for full range sound—including an extra speaker behind the viewer and one speaker for low-frequency effects.
Absorption
The action or quality of surfaces to soak up rather than reflect sound waves.
Acoustics
The production, control, transmission, reception and effects of sound in any environment, such as a living room.
Ambience
The portion of sound that results from reverberations from the surrounding environment, rather than directly from the sound source
Amplifier (amp)
A device that increases the amplitude of an electrical signal, normally fed to a loudspeaker.
Amplitude
The size of a signal, such as the voltage given out by an amplifier or the loudness of sound produced by a speaker.
Analog
Data characterized by being continuously variable (rather than making discrete jumps, as is the case with the ones and zeros in a digital signal). In the audio context, such data is usually stored as continuously varying physical undulations (vinyl albums) or as variations in a magnetic medium (tape). See Digital
Center channel speaker
In home theater surround sound, onscreen dialog and special effects are decoded from the stereo signal and sent to this speaker, which is mounted above or below the TV.
Channel
The path an audio signal travels to a speaker during playback. The number of channels varies depending on the audio source. Mono signals found in older TV programs have one channel of sound. Stereo signals have two channels, one path for left and one path for right. Surround sound signals include 5+ channels with paths for each front, center and rear speaker.
Coaxial digital cable
A popular connector for moving digital audio signals from one component to another, used with standard, RCA-type jacks and plugs. See RCA connector.
Compact disc (CD)
A plastic-coated, metalized disc that stores digitally encoded music for high-quality playback when read by a laser beam in a compact disc player.
CD-R (compact disc-recordable)
Recordable CDs that can be written to (i.e., recorded on) once and played like a regular CD in almost all home, car and portable players as well as computer CD drives. When a CD-R has been recorded and finalized it cannot be recorded on again.
CD-RW (compact disc-rewritable)
Rewritable CDs that can be written to (i.e., recorded on) repeatedly and played like a regular CD in almost all home, car and portable players as well as computer CD drives. A CD-RW can be erased and recorded on up to 1,000 times.
CD-ROM (compact disc-read only memory)
A standard compact disc used to store digital data files (e.g., large software programs) that can be read by a computer
Crossover
A circuit that divides electrical audio signals into lower and higher frequencies and sends them to the appropriate loudspeaker drive units (i.e., high frequencies to tweeters, low frequencies to woofers).
Digital
Used in an audio context, a method of representing and storing audio information with numbers, generally ones and zeros. At some point in the system, the digital signal has to be changed to an analog electrical signal in order to be played through loudspeakers, headphones ect. See Analog.
Distortion
Unwanted changes in the sound of music and movies when they are played on a sound system which cause sound other than that present in the recording to be reproduced along with the recording, sometimes the result of overloading.
Dolby® Digital*
Trade name for a digital audio format used on most DVDs, all HDTV programs and select satellite TV broadcasts.
*Dolby and the double-D symbol are trademarks of Dolby Laboratories. Manufactured under license from Dolby Laboratories.
Dolby® Digital EX
Encoding technology with a sixth channel of sound (the original Dolby Digital format has up to 5.1 channels) to deliver a 6.1-channel sound through a speaker or speakers located behind the viewer.
DVD
A digital video disc (or digital versatile disc) that looks like a CD but thatcontains high-quality video and multichannel audio for movies. A DVD can contain up to eight soundtracks or different language versions of a movie. The audio/video/data storage system based on 12- and 8-cm optical discs.
Driver
An individual speaker within a system. See Tweeter, Woofer
Equalization
Adjusting the tonal quality of a sound to compensate for losses that occur during recording or reproduction or to correct for the acoustic qualities of a listening space.
Fidelity
Recording or reproduction quality.
Frequency
The number of complete oscillations per second of periodic energy radiated as sound waves (Hz). Audible frequencies are commonly defined as ranging from 20 to 20,000 cycles per second. See Hertz
Full range
A speaker that reproduces all or almost all audible frequencies.
Hertz (Hz)
The standard unit of frequency, equivalent to one cycle per second. See Frequency
HDTV
High-definition television is a digital television format that delivers sharper picture quality with more lines of resolution.
High frequencies
Higher audio frequencies, usually taken as frequencies above about 2,000 Hz.
IR (infrared)
Pertains to the type of remote that sends/receives commands on an infrared light beam.
LFE (low frequency effects)
Refers to the deep, rumbling effects that represent the .1 of 5.1- or 6.1-channel surround sound. LFE make explosions and other room-shaking movie scenes more realistic.
Low frequencies
The lower audio frequencies, generally taken to mean below the 100 Hz to 200 Hz region.
Loudspeaker
Converts an electrical signal from an amplifier into sound waves. See Tweeter, Woofer
Midrange frequencies
Frequencies in the middle of the audio band can range anywhere from several hundred Hz to several thousand Hz.
MIDI (musical instrument digital interface)
An industry-standard digital system for connecting computers and musical instruments and for transmitting signals between any combination there of.
Mono
Short for Monophonic, which means a signal designed to be played back through a single sound source and which contains no directional information.
MP3
A compression format for digital files that makes digital music files small enough to be shared over the Internet, without radically degrading audio quality (if the amount of compression chosen is not excessive). A compressed audio format that allows you to record many hours of music on a single CD.
Passive crossover
Circuit that divides electrical audio signals into lower and higher frequencies and sends them to the appropriate loudspeaker drive units (i.e., high frequencies to tweeters, low frequencies to woofers).
Playback
The reproduction of recorded audio or video
Port
An opening in a speaker enclosure designed to act together with the air in the enclosure so the back of a driver can produce output over a narrow band of low frequencies to reinforce sound radiated directly by the driver.
Power amplifier
A device that increases the amplitude of an electrical signal.
Preamplifier / preamp
An amplifier that operates at very low signal levels to boost weak signals before feeding them to a power amplifier. Generally includes controls such as volume control and tone controls and inputs and switching for use with multiple different sources such as CD, FM radio and DVD ect.
Radio frequencies (RF)
Periodic electrical signals transmitted through air or space.
RCA connector
Common audio connector found in home entertainment systems that passes line-level audio signals between components.
Reflection
Used in an audio context, the action or quality of surfaces causing sound waves to bounce back rather than be absorbed.
S-video inputs / outputs
A connection system used to pass the S-video signals that generally provide better picture quality than standard composite video signals.
Sine wave
The waveform of a pure tone, i.e. a single frequency. All audio signals can be broken down into combinations of sine waves.
Soundstage
An audio system's ability to place the "image" of where each musician is playing on an imaginary stage in front of the listener, creating the feeling of a live performance.
Speaker
Converts an electrical signal from an amplifier into sound waves. See Tweeter, Woofer
Speaker cabinet
The box or enclosure that holds speaker drive units such as full-range speakers, woofers and tweeters, ect.
Stereo
A recording made with two or more microphones to capture the spatial characteristics of a performance or production and played back through two separate channels (or signal paths) to two spaced-apart loudspeakers. Creates the perception of a similar spatial performance to that desired by the recording engineer, frequently with different sound sources being heard to come from different places.
Surround sound
A movie recording technique that, when paired with a home theater surround speaker system, puts the viewer in the center of the action with sounds that move front to back, side to side.
Surround speakers
Home theater speakers placed to the side or rear of the listener to deliver a movie theater-like experience.
Three-way speaker
A system with three different speakers covering three frequency ranges (woofer, midrange and tweeter) located at or in each speaker cabinet.
Tweeter
A speaker designed to reproduce only high frequencies.
Two-way speaker
A system with two different speakers covering different frequency ranges (woofer and tweeter) located at or in each speaker cabinet.
Watt
Unit of electrical power.
Woofer
A speaker designed to reproduce only low frequencies.
XLR connector
A three-pin connector commonly used to carry balanced audio signals.
Y cord
A three-connector cable that,s split so one source can feed two destinations i.e. a mono signal can feed each channel in a stereo system (it will not produce stereo sound, but rather the same signal from each channel).
