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Backlighting
A technique of illuminating the buttons and keys on a remote control so they can be identified in a dark room.
Balance
A control that changes the relative volume level in two or more channels
Balanced
When positive and negative signal wires have a separate earthed (grounded) shield around them to improve interference rejection. Unbalanced connections use a coaxial cable with a single core and the outer shield doubles as the signal return path. are less apt to pick up external noise.
Band-pass Filter
An electric circuit designed to pass only middle frequencies.
Bandpass
A two-part filter that cuts both higher and lower frequencies around a center band. A bandpass enclosure cuts high frequencies by acoustic cancellation and low frequencies by natural physical limitations on bass response.
Bandwidth
The total frequency range of any system.
Bass
The low end of the audio frequency spectrum, from approximately 20 Hz up to 400 Hz.
Bass Blocker
First order high-pass crossovers (non-polarized capacitors), generally used on midbass or dash speakers to keep them from reproducing deep bass frequencies.
Bass Drive Unit (Woofer)
A drive unit designed to produce bass frequencies only. In classic two-way speakers the bass drive units are more accurately described as bass/midrange units.
Bass-Reflex
A type of loudspeaker enclosure in which the sound emitted from the back of the woofer's diaphragm is used to augment low-frequency output by feeding it through a port of passive radiator.
Beaming
The tendency of a loudspeaker to concentrate the sound in a narrow path instead of spreading it out.
Bessel Crossover
A type of crossover design characterized by having a linear or maximally flat phase response. Linear phase response results in constant time-delay (all frequencies within the passband are delayed the same amount). Consequently the value of linear phase is it reproduces a near-perfect step response with no overshoot or ringing. The downside of the Bessel is a slow roll-off rate. The same circuit complexity in a Butterworth response rolls off much faster.
Bi-Amplification
The use of two amplifiers, one for the lows, one for the highs in a speaker system. Bi-amplification can be built into the speaker design or accomplished with the use of external amplifiers and electronic crossovers.
Bi-polar
1) The condition of possessing two pole sets. In a conventional (non-FET) transistor, one pole set exists between the base and collector, and the other pole set exists between the base and emitter. 2) Speakers that consist of two driver arrays facing opposite directions and wired in electrical phase with one another to create a more diffuse soundstage.
Bi-Wiring
The use of two pairs of speaker wire from the same amplifier to separate bass and treble inputs on the speaker.
Bit
Originally short for Binary Digit. In digital, the small unit of information. A bit represents either an on of off value represented by a 0 or 1.
Bit Stream
Refers to a stream of bits transmitted over a communications line between two devices.
Black Level
Light level of the darker portions of a video image. A black level control sets the light level of the darkest portion of the video signal to match that of the display's black level capability. Black is, of course, the absence of light. Many displays, however, have as much difficulty shutting off the light in the black portions of an image as they do creating light in the brighter portions. CRT-based displays usually have better black levels than DLP, plasma, and LCD, which rank, generally, in that order.
BNC
A type of 75 ohm connection often used in video and digital audio. The BNC format utilizes a locking adapter.
Boomy
The smearing of transients that makes bass reproduction sound muddled, usually because of improperly designed sealed (to small), ported (to small or tuned improperly), and bandpass enclosures.
Bridging
combining both left and right stereo channels on an automotive amplifier into one higher powered mono channel. When an amplifier is bridged, the impedance that the amplifier sees is calculated based upon the output of both stereo channels. Here is a simple formula to help define this:
Bridged Mono Impedance = (Y / X)/2
Y = impedance of driver(s) (both drivers should be identical)
X = # of drivers in circuit
Based on this formula, hooking up one 4 ohm sub bridged mono would be equal to hooking up two 2 ohm subs in stereo, one to each channel.
Brightness
For video, the overall light level of the entire image. A brightness control makes an image brighter; however, when it is combined with a contrast, or white level control, the brightness control is best used to define the black level of the image. For audio, something referred to as bright has too much treble or high-frequency sound. (See also Black Level)
Butterworth Crossover
A type of crossover circuit design having a maximally flat magnitude response, i.e., no amplitude ripple in the passband. This circuit is based upon Butterworth functions, also know as Butterworth polynomials. |
