Compressor/Limiter Parameters
3
GC2020C Compressor/Limiter Owner’s Manual
English
Release Time
The Release Time determines how long it takes for the com-
pression to return to zero once the audio signal falls below
the threshold level. The RELEASE time range is from 50 mil-
liseconds (0.05 seconds) to 2 seconds. Like the ATTACK
control, the RELEASE control setting depends on the type
of signal being processed and the desired effect.
Figure 5
The main reason for this control is that if compression
stopped abruptly the instant the signal fell below threshold
level there would be a corresponding abrupt and unnatural
change in the level of the audio signal—particularly with
musical instruments that have a long, gentle decay slope.
Unless a particular effect is desired, set the RELEASE time to
accommodate the signal being processed.
Link
This function makes the compressor/limiter of channel A
and of channel B operate together. When a compressor/lim-
iter is used to process a stereo signal, using two independent
channels of compression causes the stereo image to waver
unsteadily, producing an unnatural effect. If the two chan-
nels are linked, however, the same compression is applied to
both channels, preserving the stereo image. When Link is
ON, the parameters of both channels are linked as follows.
• The compressor/limiters use the Threshold Level setting
of the channel whose level setting is higher.
• The expander/noise gates use the Threshold Level setting
of the channel whose level setting is lower.
• For Attack Time and Release Time, the channel with the
faster (shorter) settings determines the settings.
External trigger
Compressor/limiters normally begin compression when
they detect that the input signal has exceeded the threshold
level. However, it is also possible to use a signal other than
the input signal as the trigger. The GC2020C provides a
SIDE CHAIN OUT jack that splits the input signal and
sends it to an external device, and a SIDE CHAIN IN jack
that lets a signal from an external device control the com-
pressor/limiter. Using an external trigger allows more
sophisticated control of the GC2020C.
For example, if you connect the SIDE CHAIN OUT jack of
channel B to the SIDE CHAIN IN jack of channel A so that
channel A is controlled by an external trigger (i.e. channel
B), you can apply the compressor/limiter to the channel A
signal only when the channel B signal exceeds the threshold.
This is an easy way to produce the “ducking” effect that DJ's
or announcers use to automatically lower the volume of the
music when they speak.
By connecting an equalizer between the SIDE CHAIN OUT
and SIDE CHAIN IN jacks, boosting the 3–5 kHz region,
and setting that channel to operate with an external trigger,
you can apply a de-esser effect, in which the compres-
sor/limiter applies only to sibilant sounds (sounds with a
pronounced
S
component).
Release Time set to zero
Fast Release Time
Slow Release Time
Release Time
Input Signal
Release Time
RELEASE TIME Contorl Function
CHANNEL A
OUT
IN
INT EXT
KEY
OUT
IN
INT EXT
KEY
INPUT
+4dB
OUTPUT
+4dB
SIDECHAIN SIDECHAIN
INT EXT
CHANNEL A
OUT
IN
INT EXT
KEY
INPUT
+4dB
OUTPUT
+4dB SIDECHAIN
INT EXT
Equalizer