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.
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 effect. 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 effect. Use of extremely short release times results in rough, grainy vocoder sounds. Release values of around 8 to 10 ms are useful starting points.
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 filter 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 indefinitely. 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.
Vertically drag the Bands field to set the number of frequency bands the EVOC 20 TrackOscillator’s filter 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 find 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.