User Manual

In the case of the Comp VCA-65, since it models the old dbx Model 165A, it features the
same Compressor Curve (knee) of that unit, which was a very soft one, originating the
name "Over Easy Compressor" given by the manufacturer. This means that the unit starts
compressing way below the Threshold, but in a very subtle way, increasing the Compressor
Ratio gradually, and reaching the maximum level of compression way after the Threshold.
This allows for a very subtle and musical compression, but requires a good understanding
of this characteristic to better use it.
The way this parameter works is always influenced by the "compressor knee" or
"compressor curve" in use.
The Threshold may be put as low as -40 dB (meaning almost any audio will be compressed)
all the way up to +20 dB (which will mean basically no compression). A good range usually
varies from -10 dB to 0 dB, but it depends much on the kind of material we are compressing.
Ideally, the threshold should be just above the average signal level. By default, the Threshold
is positioned at +20 dB, which we can consider a "neutral" position.
Another important aspect is how detection works. In Comp VCA-65, detection works using
RMS (Root Mean Squared) mode. When using this kind of detection, the Threshold responds
to sharp transients in much the same way as the human hear, meaning loud but short
transients aren't perceived as being as high volume as more prolonged sounds at exactly
the same level. This allows to achieve a more natural behavior during compression.

♪: To better find the right Threshold, put the control at the highest value possible, define a very short
attack and release time, set the Compressor control to a very high compression ratio, and then start
lowering the Threshold until you hear it starting to kick in during louder passages. Then start reducing
the compression ratio to a more sensible value, and increasing the start and release times.
When the level detected is above the defined Threshold value, the Above "LED" (red light) in
the upper part of the Control Panel is On (Compression is active). When the level is below
the Threshold, the Below "LED" (green light) is On (Compression is inactive). In the transition,
the middle "LED" will momentarily turn On.
Comp VCA-65 Threshold
control defined to start at
-3 dB
Arturia - User Manual Comp VCA-65 - COMP VCA-65 CONTROL PANEL 15