If you are starting from scratch, or have gotten something out of whack and do not know exactly
what to adjust, begin by setting the controls so that all functions are disabled. Here are the control
positions for this:
EX THRESH:
EX RATIO:
COMP THRESH:
COMP RATIO:
ATTACK:
RELEASE:
LIMIT:
OUTPUT:
Naturally, the controls that need to be adjusted will depend on what you want accomplished. Here
are some suggestions to get you up and running - just follow the order listed, and leave the controls
in the above (disabled) positions if that particular function is not required.
1.
Determine the maximum output level and adjust the limit threshold so that at the loudest
peaks the output level never exceeds this point. (The action of the limiter can be seen on
the GAIN REDUCTION METER. If it never activates, there will be no LED activity.) One way
to do this is to deliberately increase the input to the compressor until the desired maximum
level is exceeded, then turn the limit threshold control CCW until it limits it to the correct level.
Reset the input level until the peaks just barely light the gain reduction meter. An alternate
method is to turn down the limit threshold until gain reduction has just occurred, then adjust
the output level control to set the desired output level.
2.
To set up a noise gate, first turn the EXPANDER RATIO control fully CW. During quiet
passages of the source (between songs, when the mics are not being used, etc.) adjust the
EXPANDER THRESHOLD CW until gain reduction is indicated (a reduction of -12 dB is a
good starting point). Re-adjust the EXPANDER RATIO to set the desired gating action when
the source changes from noise to signal. A setting of 1.1:1 has little action and can tolerate
higher threshold settings without coloring the sound, 3:1 will cause an abrupt turn on and off
when the signal changes and will probably need a lower threshold setting to prevent the
signal from dropping off when you don't want it to. You may have to go back and adjust the
threshold after the ratio has been changed, since the soft knee circuitry has more effect at
lower ratios, making the transition point less obvious.
3.
For typical vocal compression, set the COMPRESSOR RATIO control to 4:1 (a range of 2:1
to 6:1 is common) and adjust the COMPRESSOR THRESHOLD until the desired amount of
gain reduction is seen on the meter. This is a personal preference, but continuous gain
reduction greater than 9 dB (especially with higher ratios) could be excessive and could
create pumping and breathing artifacts as the signal rises and falls. Lower ratios will have a
more gentle effect. Adjust the ATTACK control to low values to suppress leading edge spikes,
or to high values to let them through (often used to pass through the click of a drum hit). The
RELEASE control is adjusted to smooth the transition as it comes out of compression. Too
quick a release will cause the signal to sound artificial. A fast attack and a short release time
will cause the compressor to track the signal very closely (and keep the dynamic range very
CONTROL SETTING PROCEDURES
min (off)
min (1.1:1)
max (+20dB)
min (1:1)
center (50msec)
center (.5 sec)
max (off)
center (0dB)
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