User Manual

4.2.3. Attack
The Attack time is a very important control in a compressor. It is with this parameter that
we define how much time the compression takes to happen when the threshold value is
reached. Manipulating this parameter can completely change the character of a sound. Very
fast attack times cause the compressor to squash the signal. On the other hand, very long
attack times will let almost all transients to pass through, which, in the worst case scenario,
can deceive completely the goal we wanted to achieve by using compression in the first
place.
So, we have to define the Attack time according to the type of audio we are dealing
with. Vocals don't deal with attack transients we usually want to preserve, therefore the
attack time there may be shorter. On complete drum tracks, where we want to achieve the
"pumping" effect, the attack time may also be positioned at a very short value (in this case
with a higher compression ratio).
As a rule of thumb, observe this: fast attacks and high ratios can reduce the sound of
unwanted transients, like a guitar pick. Slow attacks and lower ratios let transients through
and retain sound character.
To use the Comp VCA-65 as a limiter, we would use a Threshold with a value near 0 dB, with
the Compression Value set to Infinite, and the Attack time set to the minimum (very fast).
Attack times in the Comp VCA-65 are expressed as rates. Very fast attack times have a high
rate (minimum is 4000 dB/ms), while slow attack times have a low rate (1 dB/ms).
By default, the Attack time is positioned at the middle position (40 dB/ms).
Arturia - User Manual Comp VCA-65 - COMP VCA-65 CONTROL PANEL 17