Soundtoys FilterFreak - Manual (Page 30)

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Envelope Mode
The Envelope Mode employs an “envelope follower” that “follows” the volume level
of the input signal and dynamically controls the amount of filter modulation based
on volume changes in the input signal. The Envelope Mode works great on dynamic
signals that dynamically change in volume in rhythmic ways like guitar or drums.
Classic effects like the Mutron® used an envelope controlled filter to create its
effect. FilterFreak allows you to emulate this kind of effect and a whole lot more
using the envelope mode.
Threshold
The T Th hrre es sh ho olld d knob works similar to the threshold control on a compressor. It
defines at what volume the envelope follower will start “tracking” the volume
changes in the input signal. As the input level rises above the threshold, the enve-
lope follower ‘follows’ the signal and will modulate the filter frequency accordingly.
The farther above the threshold level and the louder the input signal, the more the
filter will be modulated. As the signal falls below the threshold level no modulation
occurs.
It is important to adjust the Threshold based on the type of input audio and the
amount of modulation you wish to achieve. Setting the Threshold very high will only
modulate the filter at loudest peaks of the incoming signal. Setting it too low can
cause the filter to be modulated like crazy and jump around following all the changes
in the signal. It all depends on the amount of modulation you wish to hear and there
is really no right or wrong setting.
Gain
The G Ga aiin n knob works together with the threshold control, and is similar to the ratio
control on a compressor. It determines the overall “sensitivity” of the envelope
follower, and is used to boost any signal that exceeds the setting of the threshold
control. This can be very useful when you are using either a very high threshold, or
slow attack settings. At the highest gain settings the envelope follower will begin to
function more like a gate, turning ‘on’ when the input goes above the threshold, and