Technical information

A-weighted signal to noise ratio more accurately reflects how a system's noise

performance will be perceived than an unweighted measure.

Baffle A solid surface surrounding a driver in a loudspeaker. The lower the

frequency of the sound produced by the vibrating cone of a driver, the more apt it

is to simply cause air to rush from one side of the cone to the other, rather than

produce the compression waves that constitute sound. By adding a baffle around

the driver, this increases the length of the path that air must travel, lowering the

frequency at which this destructive interference takes place. In most

loudspeakers, the enclosure forms a baffle. In the case of infinite baffle

enclosures, the enclosure is sealed (thus 'infinite') while with bass reflex speakers

a port is carefully tuned to allow energy from the back of the cone to supplement

that from the front at selected bass frequencies. Put simply, the baffle is the

front panel of the loudspeaker.

Balanced An electrical circuit in which both the signal leads (termed positive and

negative, or active and neutral) carry equal but inverse signals produced by the

source. These require three conductors: two for the signal plus a separate one

for shielding. Balanced connections are quite common in high quality (high end)

home audio products and in pro-audio, such as in recording studios. Well-

designed balanced circuits provide excellent rejection of electrical interference

generated in connecting wires and are therefore best used when long signal

cables are used, as with multi-room home audio set ups, using analogue signal

cables. Balanced connections most often use XLR plugs and sockets.

Band pass filter An electrical circuit that only permits signals between two

particular frequencies to pass through. An example is section of a crossover

network that allows only the middle frequencies to be delivered to the midrange

driver in a loudspeaker. See low pass filter and high pass filter.

Bandwidth Either the range of frequencies which a component can deal with

competently (often specified as the range across which the attenuation is no more

than 3dB), or the frequency range required to carry a signal. For example, the

bandwidth required for a composite video signal is somewhat more than 5MHz.

Bass Low frequency sounds, typically below around 150 hertz, although the

dividing line between bass and midrange is one of opinion. The human ear is less

sensitive to bass than to midrange, particularly with regards to location of source,