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Chapter 14 The EVOC 20 PS 185
Resonance is responsible for the basic sonic character of the vocoder: low settings give
it a soft character, high settings will lead to a more snarling, sharp character. Increasing
the Resonance value emphasizes the middle frequency of each frequency band.
The use of either, or both, of the Formant Stretch and Formant Shift parameters can
result in the generation of unusual resonant frequencies—when high Resonance
settings are used.
Modulation Parameters
The Modulation (LFO) area offers two LFOs to control the Formant Shift and Pitch
parameters of the EVOC 20 PS. The LFOs can run free or synchronized to the song’s
tempo.
• Pitch LFO, on the left-hand side, controls Pitch modulation (Vibrato) of the built-in
synthesizer’s oscillators. It is hardwired to accept data from the modulation wheel of
your MIDI keyboard (or corresponding MIDI data) to control modulation intensity.
• Shift LFO controls the Formant Shift parameter of the Synthesis filter bank to produce
dynamic phasing-like effects.
Wave
These two switches allow the selection of the waveform type used by Pitch LFO and
Shift LFO. A selection of Triangle, falling and rising Sawtooth, Square up and down
around zero (bipolar, good for trills), Square up from zero (unipolar, good for changing
between two definable pitches), a random stepped waveform (S&H), and a smoothed
random waveform is available for each LFO.
Intensity/Int via Whl
The Intensity slider controls the amount of Formant Shift modulation by the Shift LFO.
The Int via Whl slider for the Pitch LFO features a multi-part slider. The intensity of LFO
pitch modulation can be controlled by the modulation wheel of an attached MIDI
keyboard. The upper half of the slider determines the intensity when the modulation
wheel is set to its maximum value, and the lower half when set to its minimum value.
By clicking and dragging in the area between the two slider segments, you can
simultaneously move both.