Audio Damage Filterstation - Manual (Page 14)

Envelope Follower
Filterstation can respond to the loudness of the incoming signal with its envelope follower. The envelope
follower generates a modulation signal that rises and falls in proportion to the loudness of the input signal,
and can be used—like the LFO—to control the frequencies of either of the filters, or both.
The envelope follower has two parameters for adjusting how it responds to the signal: ENV ATTACK and ENV
DECAY. ENV ATTACK controls how quickly the envelope follower‘s output increases when the level of the
input signal increases. ENV DECAY does the opposite, controlling how fast the output decreases when the
input signal‘s level falls. If you‘re using the envelope follower with a signal like drums or electric bass, you‘ll
probably want to use an attack value near zero so that the envelope follower responds rapidly. Adjust the
decay setting to smooth out or extend the response of the envelope
follower as the notes die away. With sustained sounds like synthesizer
pads, you can use a longer attack time to create fade-in effects that open
the filters slowly as you hold chords. In conjunction with the VCA filter
mode, a longer attack time can create slow-gear effects for guitar.
The envelope follower adds the left and right channels of the input signal together, regardless of which routing
configuration is in use.
Envelope Amount
Each filter has its own ENVELOPE AMOUNT control, which sets how much the envelope follower changes the
filter‘s frequency. These controls have a range of -100 to +100. Larger values, either positive or negative,
have a greater effect on the filter. If you set the ENVELOPE AMOUNT control to a positive value, the envelope
follower will increase the filter‘s frequency when the input signal gets louder. If you set the ENVELOPE
AMOUNT to a negative value, the envelope follower will decrease the filter‘s frequency.
Although Filterstation has only one envelope follower which is shared by the two filters, you
can set their envelope amounts to opposite polarities and cause the filters to move in different
directions. You can also apply different amounts of LFO and envelope modulation to the two
filters.
Side-Chain Input (VST3 Only)
There is a variant of the VST3 version of Filterstation called Filterstation Side-Chain. This version of the plug-
in has an auxiliary mono input that does not pass through the filters, but is fed directly to the envelope
follower. This lets you use a different instrument to control the filters, similar to how a side-chain compressor