Appendix A - Glossary - Avalon VT-737SP Operation Manual

Appendix A - Glossary

amplification - The process by which a signal
level is increased.
amplitude - The distance above or below the
centerline of a signal's waveform. The greater the
distance from the centerline, the larger the pres-
sure variation or electrical signal.
attack - The initial transient or first part of the
envelope of a signal. The beginning of a note.
attenuate - To reduce the signal level.
balanced - In a classic balanced audio circuit, the
two legs of the circuit (+ and -) are isloated from
the circuit ground by exactly the same imped-
ance. Additionally, each leg carries the signal at
exactly the same level but with opposite polarity.
Balanced input circuits can offer excellent rejec-
tion of noise and grounding loops.
balanced line - A cable having two conductors
and a ground connection and often surrounded
by a shield. With respect to ground, the conduc-
tors are at equal potential but opposite polarity.
These lines are often used in professional setting
to reduce or eliminate induced noise and interfer-
ence from external electromagnetic sources.
bandwidth - The band of frequencies that pass
through a device with a loss of less than 3dB,
expressed in hertz or in musical octaves.
cardioid - Refers to the shape of the sensitivity
pattern of certain directional microphones.
channel - A single functional path in an audio
circuit.
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clipping - A cause of audio distortion that is
the result of excessive gain requiring the peaks
of the audio signal to rise above the capabili-
ties of the circuit.
compressor - In effect, an automatic fader.
When the input signal exceeds a predeter-
mined level, called the threshold, the gain is
reduced by the compressor and the signal is
attenuated.
compression ratio - The ratio of signal
dynamic range between the compressor input
and the outupt above the device's set thresh-
old point (such as 2:1, 4:1, 20:1).
condenser - Refers to a type of microphone
that uses a capacitor as the sound pickup
element. Condenser mics require electrical
power to run internal amplifiers and maintain
an electrical charge on the capacitor. They are
typically powered by internal batteries or
"phantom power" (48v) supplied by an external
source, such as a preamplifier or mixing con-
sole.
console - A term for a sound mixer, usually a
large desk-type mixing board used to mix
together multiple track musical material.
crosstalk - The unwanted leakage of a signal
from one channel or track onto another.
decibel (dB) - A unit of audio measurement of
sound pressure level (SPL), signal level, and
changes of difference in signal level. The deci-
bel is a logarithmic (log) mathematical function
that reduces large numeric values into smaller,
more manageable numbers. Decibel is calcu-
lated as 10 times the log of the ratio of two
powers, and 20 times the log of the ratio of two
voltages.
Avalon Vt-737sp Operation Manual
Glossary