Specifications
Pro Tools Reference Guide56
Release
The Release control sets how long it takes for
the gate to close after the input signal falls below
the threshold level and the hold time has passed.
Knee
The Knee control sets the rate at which the Ex-
pander/Gate reaches full effect once the thresh-
old has been exceeded.
Hysteresis
The Hysteresis (Hyst) control lets you adjust
whether or not the gate rapidly opens and closes
when the input signal is fluctuating near the
Threshold. This can help prevent undesirably
rapid gating of the signal. This control is only
available when
Ratio is set to Gate, otherwise it
is greyed out.
Compressor/Limiter Controls
Threshold
The Threshold control sets the level that an input
signal must exceed to trigger compression or
limiting. Signals that exceed this level will be
compressed. Signals that are below it will be un-
affected.
Attack
The Attack control sets the attack time, or the
rate at which gain is reduced after the input sig-
nal crosses the threshold.
The smaller the value, the faster the attack. The
faster the attack, the more rapidly the Compres-
sor/Limiter applies attenuation to the signal. If
you use fast attack times, you should generally
use a proportionally longer release time, partic-
ularly with material that contains many peaks in
close proximity.
Ratio
The Ratio control sets the compression ratio, or
the amount of compression applied as the input
signal exceeds the threshold. For example, a 2:1
compression ratio means that a 2 dB increase of
level above the threshold produces a 1 db in-
crease in output. The compression ratio ranges
from 1:0:1 to 20:0:1.
Once the
Ratio control passes 20:0:1 the Com-
pressor/Limiter effect functions as a limiter
rather than a compressor.
At the limiter setting (
LMTR), for every decibel
that the incoming signal goes over the set
Threshold, 1 dB of gain reduction is applied.
Once the
Ratio control passes the LMTR setting,
it provides negative ratio settings from –20:0:1
to 0:1.
Dynamics section, Compressor/Limiter tab
Compressor/Limiter Ratio set to LMTR
Compressor/Limiter Ratio set to a negative value