LA Audio GOC20, Operation Manual

Page: 9 / 17

Page 9
In LINK mode Channel 1 becomes the MASTER controller for both channels. The controls, switches
and leds associated with Channel 2 are in-operative in this mode.
The GCX20 combines the signals from both channels so that the input to either channel (exceeding
Threshold) triggers the gate.
4.2 COMPRESSOR SECTION
Dual Compressor/Gate
STEREO
DUAL
LINK
0
+10
- 10
+ 20
2
6
20
0
+10 -10
+20 - 30
- 20
THRESHOLD THRESHOLD RELEASE
1
FAST
GATE
SLOW
- 20
GAIN RATIO
dB :1 dB
ATTACK
BYPASS BYPASS
POWER
- 20 -15 -10 - 6 - 4 - 2
COMPRESSOR 2 GATE 2
- 40
0
- 30
- 10
+16 - 50
+10
FAST SLOW
RELEASE
GAIN REDUCTION
MASTER
dB t
THRESHOLD control
This control sets the signal level above which compression starts. The Threshold range is -30dBu
(CCW) to +20dBu (CW).
RATIO control
Ratio defines the amount of compression applied to the input signal once it has exceeded the
Threshold level. A Ratio setting of 2:1, for example means that for every 2dB that the input exceeds
the Threshold, the output will increase by 1dB. The following graph shows the relationship between
input and output levels for various Ratios -
INPUT
OUTPUT 1:1
2:1
4:1
10:1
20:1
THRESHOLD
0dB
0dB
Fig: 4.3.1 Effect of Ratio control on O/P levels.
A RATIO of 1:1 gives no compression and 20:1 gives no increase in output level no matter how far
the signal increases above Threshold.
The ratio curves shown in Fig 4.3.1 are Hard-knee where the change in gain is abrupt. The GCX20
has a Soft-knee control system which provides a gradual change between compression levels.
GAIN
control
Because compression is a gain reduction process, the output of the compressor is often at a lower
level than the normal operating level.