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172 Chapter 13 Vocoder—Basics
Treatment of the Side Chain signal (speech) with Compressor, Shelving Filter and Gate.
The Silver Compressor, Silver Gate or another EQ are well-suited for these purposes.
Achieving the Best Analysis and Synthesis Signals
For good speech intelligibility, please keep these points in mind:
• The spectra of the analysis and synthesis signals should overlap almost completely.
Low male voices with synthesis signals in the treble range do not work well.
• The synthesis signal must be constantly sustained, without breaks. The track should
be played legato, as breaks in the synthesis signal will stop the vocoders output.
Alternatively, the Release parameter of the synthesis signal (not to be confused with
the Release time of the analysis section) can be set to a longer time. Nice effects can
also be achieved by the use of a reverberation signal as a synthesis signal. Note that
the two latter methods can lead to harmonic overlaps.
• Do not overdrive the Vocoder. This can happen easily, and distortion will occur. Lower
the Gain of the compressor in the Side Chain track, to avoid this problem.
• Enunciate your speech clearly, if the recording is to be used as an analysis signal.
Spoken words, with a relatively low pitch, work better than sung vocals—even if the
creation of vocoder choirs is your goal! Pronounce consonants well.