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160 Chapter 14 EVOC 20 PolySynth
Release
The Release parameter determines how quickly each envelope follower (coupled to
each analysis filter band) reacts to falling signals. Longer Release times cause the
analysis input signal transients to sustain longer at the vocoder’s output.
Note: A long Release time on percussive input signals (a spoken word or hi-hat part, for
example) will translate into a less articulate vocoder effect. Note that Release times that
are too short result in rough, grainy vocoder sounds. Release values of around 8 to
10 ms have proven to be useful starting points.
Freeze
When enabled, the current analysis sound spectrum is held infinitely. The frozen
analysis signal can capture a particular characteristic of the source signal which is then
imposed as a complex sustained filter shape on the Synthesis section. While Freeze is
enabled, the analysis filter bank ignores the input source, and the Attack and Release
parameters have no effect.
Using a spoken word pattern as a source, for example, the Freeze button could capture
the attack or tail phase of an individual word within the pattern—the vowel a, for
example.
Another use of the Freeze button (which can be automated) could be to compensate
for people’s inability to sustain sung notes for a long period, without taking a breath. If
the synthesis signal needs to be sustained, when the analysis source signal (a vocal
part) isn’t, Freeze can be used to lock the current formant levels (of a sung note)—even
during gaps in the vocal part—between words in a vocal phrase.
Bands
The Bands parameter determines the number of frequency bands used by the
EVOC 20 PolySynth.
The greater the number of bands, the more precisely the sound can be reshaped. As
the number of bands is reduced, the source signal’s frequency range is divided up into
fewer bands—and the resulting sound will be formed with less precision by the
synthesis engine.
Note: Increasing the number of bands also increases the processor overhead.
You may find that a good compromise between sonic precision—allowing incoming
signals (speech and vocals, in particular) to remain intelligible—and resource usage, is
around 10 to 15 bands.