Mackie glossary Manuel D’Utilisation
15
RFI
Radio Frequency Interference. High frequency
radiation that often results from sparking cir-
cuits. This can be manifested in a number of
ways in audio systems, but is usually evident as
a high-frequency buzz or hash sound.
radiation that often results from sparking cir-
cuits. This can be manifested in a number of
ways in audio systems, but is usually evident as
a high-frequency buzz or hash sound.
ROM
Read only memory is a type of computer mem-
ory that cannot be written to, but only read
from.
ory that cannot be written to, but only read
from.
RMS
An acronym for root mean square, a conven-
tional way to measure the effective average
value of an audio signal or other AC voltage.
Most AC voltmeters are calibrated to read RMS
volts, though on many meters that calibration
is accurate only if the waveform is sinusoidal.
tional way to measure the effective average
value of an audio signal or other AC voltage.
Most AC voltmeters are calibrated to read RMS
volts, though on many meters that calibration
is accurate only if the waveform is sinusoidal.
S
Sa value
A measure of the relative liveness of a room. A
low Sa means a very live room, and a high Sa
means a dead room. S = the total surface area
of the room, and a = the average absorption
coefficient of all the surfaces.
low Sa means a very live room, and a high Sa
means a dead room. S = the total surface area
of the room, and a = the average absorption
coefficient of all the surfaces.
sampling frequency
This is the rate at which an analog signal is sam-
pled during the analog-to-digital conversion
process. The sampling rate used for compact
discs is 44.1 kHz, but professional recordings
are often sampled at higher sample rates, such
as 96 kHz or even 192 kHz (that’s 192,000 sam-
ples per second!).
pled during the analog-to-digital conversion
process. The sampling rate used for compact
discs is 44.1 kHz, but professional recordings
are often sampled at higher sample rates, such
as 96 kHz or even 192 kHz (that’s 192,000 sam-
ples per second!).
send
A term used to describe the output of a second-
ary mix of the input signals, typically used for
foldback monitors, headphone monitors or
ary mix of the input signals, typically used for
foldback monitors, headphone monitors or
effects devices. Mackie mixers call it an Aux
Send.
Send.
shelving
A term used to describe the shape of an equal-
izer’s frequency response. A shelving equal-
izer’s response begins to rise (or fall) at some
frequency and continues to rise (or fall) until it
reaches the shelf frequency, at which point the
response curve flattens out and remains flat to
the limits of audibility. If you were to graph the
response, it would look like a shelf. Or more
like a shelf than a hiking boot. See also peaking
and dipping.
izer’s frequency response. A shelving equal-
izer’s response begins to rise (or fall) at some
frequency and continues to rise (or fall) until it
reaches the shelf frequency, at which point the
response curve flattens out and remains flat to
the limits of audibility. If you were to graph the
response, it would look like a shelf. Or more
like a shelf than a hiking boot. See also peaking
and dipping.
signal-to-noise ratio (S/N)
This is a specification that describes how much
noise an audio component has compared to the
signal. It is usually expressed in dB below a
given output level.
noise an audio component has compared to the
signal. It is usually expressed in dB below a
given output level.
slap, slapback
A single-delay echo without any repeats. Also
see echo.
see echo.
solo
Italian for alone. In audio mixers, a solo circuit
allows the engineer to listen to individual chan-
nels, buses or other circuits singly or in combi-
nation with other soloed signals.
allows the engineer to listen to individual chan-
nels, buses or other circuits singly or in combi-
nation with other soloed signals.
sound reinforcement
A system of amplifying acoustic and electronic
sounds from a performance or speech so that a
large audience can hear clearly. Or, in popular
music, so that a large audience can be excited,
stunned, or even partially deafened by the tre-
mendous amplification. Means essentially the
same thing as PA (Public Address).
sounds from a performance or speech so that a
large audience can hear clearly. Or, in popular
music, so that a large audience can be excited,
stunned, or even partially deafened by the tre-
mendous amplification. Means essentially the
same thing as PA (Public Address).
spaghetti
That mess of wires and cables in the back of
your rack and/or console. You really can tame
this.
your rack and/or console. You really can tame
this.