API 2500 - Page 6

THRESH:
This control sets the THRESHHOLD from +10 dBu to -20 dBu. Both channels are
set independently with this control. Each channel has its own RMS detector and
can operate as two single compressors or one stereo compressor. Even when
using the LINK control, each channel ALWAYS has its own RMS detector for
accuracy. This control is continuously variable. The THRESH control also
effects the gain when in the AUTO gain make-up mode.
ATTACK:
This control sets the ATTACK time of each channel from 30 microseconds to 30
milliseconds. There are seven positions to choose from, 30u/sec, 100u/sec,
300u/sec, 1 m/sec, 3 m/sec, 10 m/sec and 30 m/sec. This rotary switch allows
repeatability, while offering a wide range of settings.
RATIO:
This control sets the compression RATIO of each channel from 1.5:1 to INF:1 or
above 20:1. There are seven positions to choose from, 1.5:1, 2:1, 3:1, 4:1, 6:1,
10:1 and INF:1. This rotary switch allows repeatability while offering a wide range
of settings. The RATIO control also affects the gain when in the AUTO gain make-
up mode.
RELEASE:
This control sets the RELEASE of each channel of the compressor, covering a
wide range of release times including the last position, which switches it to the
VARIALBLE RELEASE control to the right of it. There are seven positions to
choose from, 50m/sec., 100m/sec, 200m/sec., 500/m/sec, 1 sec, 2 sec, and
VARIABLE.
VARIABLE RELEASE:
This control sets the RELEASE time with a continuously variable pot covering a
range from 50m/sec. to 3 seconds. This works when the RELEASE rotary switch
control is fully clockwise. This allows for a continuously variable release, with
the ability to match the "bounce" of a song with the release time.
Compressor Section
m/secdB x:1 sec
+4
+8
+10
-20
-4
-12
-8
0
THRESH
ATTACK RATIO
RELEASE
.03
.1
.3
1
3
10
30
1.5
2
3
4
6
10
.05
.1
.2
.5
1
2
oo
COMPRESSOR
sec
RELEASE
variable
.25s
.15s
50m
3s
1.5s
.75s