Technical information

allowing sub bass units to be placed away from the stereo speakers in 2.1of 5.1
set ups.
Bass extension An imprecise term concerning how low in frequency a loudspeaker
or subwoofer can still operate to produce usable output. A typical bookshelf-sized
speaker may manage a bass extension of 80 hertz (say, at -10dB), a good floor
standing speaker may manage 30 or 40 hertz, an inexpensive subwoofer 40
hertz, a middling one 25 to 30 hertz, an expensive one 16 hertz.
Bass management A facility in home theatre receivers that permits some of the
speakers in a 5.1 channel system to be specified as 'small' rather than 'large'.
'Large' speakers receive the entire signal for their respective channel, but 'small'
speakers have the bass stripped off and sent to a subwoofer.
Bass reflex A design for the enclosure of a loudspeaker. With bass reflex
speakers the enclosure has a port that permits air to flow between the interior
and exterior of the cabinet. The port is a hole, usually backed by a tube. The
dimensions of the port are carefully calculated so that it permits bass at a
selected frequency to be produced from the interior of the enclosure (driven by the
back of the woofer's cone). This arrangement permits a bass reflex speaker to
generally achieve greater efficiency than an acoustic suspension speaker, and it
extends the depth at which bass may be produced without significant attenuation.
However for frequencies below the band produced by the port, the output drops
off rapidly.
Belt Sometimes describes the loop of material that is used to transmit rotational
energy from motor to record platter on a turntable. Also, a set of ‘extreme’ audio
system tweaks popularized in the 1980s and beyond by Peter Belt in the United
Kingdom. Some subjective reviewers have, over the years, sworn by these (and
other) measures to improve the perceived sound quality of home audio systems.
Many of Peter Belt’s ideas do seem ridiculous, but he did much to popularize the
notion that audio components and audio rooms can be improved through
‘treatment’, much of which is unmeasurable, and therefore very subjective.
Beta or Betamax. The first widely-used consumer-level video recording system on
the market. Developed by Sony in the late 1970s, it eventually lost out to the rival
VHS system, which came to market about a year later, primarily because of
shorter playing and recording times.
Bipole A loudspeaker designed to offer well-dispersed sound by firing its high
frequencies, and in some models its full frequency range, in two opposing
directions. Unlike dipole speakers, the sound is in phase from all the drivers.