User Guide

Chapter 6 Filter 103
LFO Parameters
You set the waveform of the LFO by clicking one of the Waveform buttons. The choices
are: descending sawtooth (saw down), ascending sawtooth (saw up), triangle, pulse
wave, or random (random values, Sample & Hold). Once you select a waveform, you
can shape the curve with the Pulsewidth slider. Use the Coarse and Fine Frequency
knobs to set the LFO frequency. The Rate Mod. (Rate Modulation) knob controls
modulation of the LFO frequency independent of the input signal level. If the input
signal exceeds the Threshold level, the modulation width of the LFO increases from 0
to the Rate Mod. value. You can also define the amount of time this process takes, by
entering the desired value with the Decay/Delay knob. If the Retrigger button is turned
on, the waveform starts at 0° whenever the Threshold is exceeded. For stereo instances
of the AutoFilter, you can control the phase relationships of the LFO modulations on
the two stereo sides with the Stereo Phase knob.
Turning on Beat Sync synchronizes the LFO to the sequencer’s tempo. The speed values
include bar values, triplet values, and more. These are determined by the Rate knob
next to the Beat Sync button. Use Sync Phase to shift the phase relationship between
the LFO and the sequencer.
Distortion Parameters
The Distortion Input and Output parameters let you individually control pre-input and
post-output distortion. Although the two distortion modules work in an identical way,
their respective positions in the signal chain—before and after the filter, respectively—
result in remarkably different sounds.
Output Parameters
The Dry Signal parameter sets the level ratio of the non-effected (dry) signal mixed
with the processed signal. The Main Out parameter can lower the output volume by as
much as 50 dB, allowing you to compensate for higher levels caused by adding
distortion or other processing.
EVOC 20 Filterbank
The EVOC 20 Filterbank consists of two formant filter banks, which are also used in the
EVOC 20 PolySynth vocoder plug-in for Logic Pro and MainStage.
The input signal passes through the two filter banks in parallel. Each bank features
volume faders for ten frequency bands, allowing you to adjust the volume of each
band independently. Setting a fader to its minimum value completely suppresses the
formants in that band. You can control the position and width of the filter bands using
the Formant Stretch and Formant Shift parameters. In addition, you can also crossfade
between the two filter banks.
For more information on filter banks, refer to “How Does a Filter Bank Work?” on
page 207.