Symetrix 425 - Initial Settings; Initial Setup and Level Adjustment; Refining Your Settings

6.2 Settings
Make your initial switch and control settings as follows:
Usage Switch Setting
Dual mono
IN/BYPASS
depressed
STEREO/DUAL
out
Stereo
IN/BYPASS
depressed
STEREO/DUAL
depressed
DUAL
LINK
LIMIT
COMPRESSOREXPANDER
-20
+5
THRESHOLD (dBu) RELEASE
FAST
SLOW
-18 -12 -6 -2 -10 -12 -15 -25
-40
-10
BYPASS
RATIO (X:1)RELEASE
1
10
2
-8 -6 -4 -2
FAST
SLOW
-12 -9 -6 -3
+5
BYPASS
-10
GAIN (dB)
BYPASS
IN
0
+20
STEREO
DUAL MONO
CLIP0VU-10 -20 STEREO
OUT
BYPASS
-5 -30 +10 -25
THRESHOLD (dBu) THRESHOLD (dBu)
-2.5 +12.5
+10
+5 +15
1.3 2.5
Control Setting Control Setting Control Setting
Expander: Compressor: Peak Limiter:
THRESHOLD
-20
THRESHOLD
-10
THRESHOLD
+5
RELEASE
12 o'clock
RELEASE
12 o'clock
RATIO
10:1
GAIN
0
6.3 Initial Setup
The 425's controls and switches are now set according to the preceding section. All
connections listed in Section 6.1 are now made. The 425 should now pass signal. The LED
display should be illuminated.
Set the input level by increasing the setting of the input level control until the amber LEDs in
the
HEADROOM display illuminate. Ideally, the highest signal level should illuminate the -1 dB
LED, and the
CLIPPING LED should almost never illuminate (the CLIPPING LED operates 1 or 2
dB below clipping.).
6.4 Refining Your Settings
For most signals, the above settings should produce activity in each section of the 425. The
expander and compressor sections tend to be complementary, that is, you probably won't be
showing expansion when the signal level is high enough to cause compression.
Whenever the operation of two of the sections of the 425 overlaps (especially the compressor
and limiter sections), whichever section has the highest gain-reduction reading on its display
is the section controlling the signal at that instant.
Refine the expander
THRESHOLD setting so that the expander reduces the gain when the input
signal falls below the threshold setting. You can make the expander "ignore" momentary
lapses in signal by increasing the setting of the
RELEASE control. This also affects the rate-of-
release once the signal falls below-threshold.
Rev 2.0, 10/29/93
6-2