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Chapter 14—Dynamics Processors
03D—Owner’s Manual
Signals at and above the threshold level are compressed by the amount specified using
the Ratio parameter. The trigger signal is sourced using the KEY IN parameter.
RATIO
—This determines the amount of compression. That is, the change in output
signal level relative to change in input signal level. For a 2:1 ratio, for example, a 10 dB
change in input level (above the threshold) results in a 5 dB change in output level. For
a 5:1 ratio, a 10 dB change in input level (above the threshold) results in a 2 dB change
in output level.
KNEE
—This determines how compression is applied at the threshold point. When set
to hard, compression at the specified ratio is applied as soon as the input signal level
exceeds the specified threshold. For knee settings from 1 to 5, however, compression is
applied gradually as the signal exceeds the specified threshold, creating a more natural
sound. This is called soft-knee compression.
ATTACK
—This determines how soon the signal is compressed once the compressor
has been triggered. With a fast attack time, the signal is compressed almost immedi-
ately. With a slow attack time, however, the initial transient of a sound passes through
unaffected. Attack times from 1–5 ms are a good place to start.
RELEASE
—This determines how soon the compressor returns to its normal gain once
the trigger signal level drops below the threshold. If the release time is too short, the
gain will recover too quickly causing level pumping (i.e. noticeable gain fluctuations).
If it is set too long, the compressor may not have time to recover before the next high
level signal appears, and it will be compressed incorrectly. Release times from 0.1–0.5s
are a good place to start.
OUT GAIN
—This sets the compressor’s output signal level. It can be used to compen-
sate for the overall level change caused by the compression process.
GATE
A gate, or noise gate is essentially an audio switch
used to mute signals below a set threshold level. It
can be used to cut background noise picked up by
open microphones, noise and hiss from guitar
valve amps and effects pedals, and leakage
between drum microphones. It also has many cre-
ative uses too. For example, gating a drum sound
with a short decay time tightens up the sound.
Also, patching a gate into a droning bass synth
channel and then triggering it from the kick drum
channel allows the bass synth through only when
the kick drum is struck, adding extra “oomph” on
the beat.
Parameter
Range
THRESHOLD
–54 dB to 0 dB (55 steps)
RANGE
–70 dB to 0 dB (71 steps)
ATTACK
0–120 ms (1 ms steps)
HOLD
0.02 ms–1.96 s (sampling rate @ 48 kHz)
0.02 ms–2.13 s (sampling rate @ 44.1 kHz)
0.03 ms–2.94 s (sampling rate @ 32 kHz)
DECAY
5 ms–42.3 s (sampling rate @ 48 kHz)
6 ms–46 s (sampling rate @ 44.1 kHz)
8 ms–63.4 s (sampling rate @ 32 kHz)
–70
–60
–50
–40
–30
–20
–10
0
+10
+20
–70
–60
–50
–40
–30
–20
–10
0
+10
+20
Input Level (dB)
Output Level (dB)
Threshold = –10dB
Range = –30dB
Range = –70dB
