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Chapter 6 Filter eects 123
Use EVOC 20 TrackOscillator analysis in
You should be precise with the Analysis In parameters in order to attain the best possible
speech intelligibility and the most accurate tracking. Follow these tasks and tips to obtain the
best results.
Set Attack and Release times
m Rotate the Attack and Release knobs to set times that provide the most articulated sound.
Longer attack times result in a slower tracking response to transients—level spikes—of the
analysis input signal. A long attack time on percussive input signals, such as a spoken word
or hi-hat part, translates into a less articulated vocoder eect. Set the Attack parameter to the
lowest possible value to enhance articulation.
Longer release times cause the analysis input signal transients to sustain for a longer period at
the vocoder’s output. A long release time on percussive input signals, such as a spoken word
or hi-hat part, translates into a less articulated vocoder eect. Use of extremely short release
times results in rough, grainy vocoder sounds. Release values of around 8 to 10 ms are useful
starting points.
Freeze the input signal
m Click the Freeze button to hold, or sustain, the sound spectrum of the analysis input signal.
By freezing the input signal you can capture a particular characteristic of the signal, which is then
imposed as a complex sustained lter shape on the Synthesis section. Here are some examples
of when this could be useful:
•
If you are using a spoken word pattern as a source, the Freeze button could capture the attack
or tail phase of an individual word within the pattern—the vowel a, for example.
•
People cannot sustain sung notes indenitely. To compensate for this human limitation,
use the Freeze button. If the synthesis signal needs to be sustained but the analysis source
signal—a vocal part—is not sustained, use the Freeze button to lock the current formant
levels of a sung note, even during gaps in the vocal part, between words in a vocal phrase.
Tip: The Freeze parameter can be automated, which may be useful in this situation.
Set the number of lter bank bands
m Vertically drag the Bands eld to set the number of frequency bands the
EVOC 20 TrackOscillator’s lter bank uses.
The greater the number of frequency 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. You
may nd that a good compromise between sonic precision—allowing incoming signals such as
speech and vocals to remain intelligible—and resource usage is around 10 to 15 bands.
Tip: To ensure the best possible pitch tracking, it is essential to use a mono signal with no
overlapping pitches. Ideally, the signal should be unprocessed and free of background noises.
Using a signal processed with even a slight amount of reverb, for example, can produce unusual
results. Processing a signal with no audible pitch, such as drum loop, also delivers unusual results,
but the resulting artifacts might be perfect for your project.