Using The Vocoder - ENSONIQ DP/4 Musician's Manual

Section 5 - The Vocoder
Using the Vocoder
As you speak into the mike, play appropriate notes on the keyboard (or other controller sources)
at the same time and listen to the results. Using a vocoder may require a little practice, but can
provide some rewarding musical effects. Some common effects are to produce "robot-speech" by
talking into the mike while playing a single note, or to create choir sounds by saying "aah" or
"ooh" into the mike while playing chords on the keyboard.
Note that the pitch of the output signal is entirely determined by the pitch of the carrier input,
and is not affected by the pitch you sing into the microphone. The characteristics of the carrier
input signal also affect the vocoder quality. The carrier signal must not only contain sufficient
harmonics to cover the frequency range of the vocoder, it must be played in a pitch range that
roughly corresponds to the pitch of the microphone (vox) input. For example, it would be hard
to get good results if you are talking in a low pitched
voice, but are playing high notes on the
keyboard.
Although the Input 1 (vox) is optimized for speech, any signal source can be used. The vocoder
will apply the spectrum of any Input 1 signal to the carrier signal, which can produce some
interesting timbres.
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