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Table Of Contents
Getting the Best Results with the EVOC 20 PolySynth
Achieving a great classic” vocoder effect requires both the analysis and synthesis signals
to be of excellent quality, and it also requires care to be taken with the vocoder parameters.
These sections outline a number of tips that will help you achieve the best possible results.
Editing the EVOC 20 PolySynth Analysis and Synthesis Signals
Avoiding Sonic Artifacts in the EVOC 20 PolySynth
FM Mode EVOC 20 PolySynth Oscillator Parameters
Editing the EVOC 20 PolySynth Analysis and Synthesis Signals
The following section outlines how you can edit the analysis and synthesis signals to
achieve better speech intelligibility.
Compressing the EVOC 20 PolySynth Analysis Signal
The less the level changes, the better the intelligibility of the vocoder. You should therefore
compress the analysis signal in most cases.
Enhancing High Frequency Energy
The vocoder, in a way, always generates the intersection point of the analysis and synthesis
signals. If theres no treble portion in the analysis signal, the resulting vocoder output
will also lack treble. This is also the case when the synthesis signal features a lot of high
frequency content. Because this is true of each frequency band, the vocoder demands a
stable level in all frequency bands from both input signals in order to obtain the best
results.
Due to the way human beings hear, the intelligibility of speech is highly dependent on
the presence of high frequency content. To aid in keeping speech clear, it may be
worthwhile using equalization to boost or cut particular frequencies in analysis signals
before you process them with the vocoders.
If the analysis signal consists of vocals or speech, a simple shelving filter should be
sufficient to boost the high-mid and treble range, which is so important for speech
intelligibility.
If the synthesis signal lacks treble energy, it can be generated with a distortion effect. The
Logic Express Overdrive effect is perfect for this purpose.
Avoiding Sonic Artifacts in the EVOC 20 PolySynth
A common problem with vocoder sounds involves sudden signal interruptions (ripping,
breaking sounds) and rapidly triggered noises during speech pauses.
156 Chapter 7 EVOC 20 PolySynth