3
B
balanced input
An input consists of two leads, neither of which
is common to the circuit ground. This is a “dif-
ferential pair”, where the signal consists of the
difference
in voltage between the two leads. Bal-
anced input circuits can offer excellent rejec-
tion of common-mode noise induced into the
line.
balanced output
In a classic balanced audio circuit, the output is
carried on two leads (high or + and low or -)
which are isolated from the circuit ground by
exactly the same impedance.
A symmetrical balanced output carries the same
signal at exactly the same level but of opposite
polarity with respect to ground.
A special case of a balanced output carries the
signal on only one lead, with the other lead
being at zero voltage with respect to ground,
but at the same impedance as the signal-carry-
ing lead. This is sometimes called
impedance bal-
anced
.
bandwidth
The band of frequencies that pass through a
device with a loss of less than 3 dB, expressed in
Hertz or in musical octaves. Also see Q.
bit
The smallest component of a digital word, rep-
resented by either a one or a zero.
bridged mono
A mode of operation for a stereo amplifier that
routes a single input to both channels, but
inverts the signal on channel 2, thereby provid-
ing twice the voltage of an individual output by
connecting the speaker between the two posi-
tive output terminals (the negative output ter-
minals are not used).
bus
An electrical connection common to three or
more circuits. In mixer design, a bus usually
carries signals from a number of inputs to a
mixing amplifier, just like a city bus carries peo-
ple from a number of neighborhoods to their
jobs. It comes from the British “omnibus”.
C
Cannon
A manufacturer of electrical connectors who
first popularized the three-pin connector now
universally used for balanced microphone con-
nections. In sound work, a Cannon connector
is taken to mean a Cannon XLR-3 connector or
any compatible connector. You can tell an
audio geezer because he refers to this connector
as “Cannon”. Today the term “XLR” is more
common.
cardioid
Heart-shaped. In sound work, cardioid refers to
the shape of the sensitivity vs. direction plot for
a particular style of directional microphone. A
cardioid mic rejects sound arriving from the
rear.
channel
A functional path in an audio circuit: an input
channel, an output channel, a recording chan-
nel, the left channel and so on.
channel strip
The physical realization of an audio channel on
the front panel of a mixer; usually a long, verti-
cal strip of controls.
chorusing
A time-based effect available in some digital
delay effects units and reverbs. Chorusing
involves a number of moving delays and pitch
shifting, usually panned across a stereo field.
