A channel vocoder: your voice shapes a synthesizer, so the synth seems to speak or sing. Play chords on a keyboard while you talk, or let the vocoder follow the pitch of your voice on its own for the classic robot voice.
The idea
A vocoder splits two signals into matching frequency bands. One is the voice, the modulator: the vocoder measures how loud each of its bands is from moment to moment. The other is a synth sound, the carrier: each of its bands is opened and closed by the matching band of the voice. The result has the synth's texture and the notes you play, with the vowels and articulation of the voice.
Consonants such as s, t and f have little pitch and would vanish in a plain vocoder. A detector spots them and adds noise, the voice's own highs, or a blend of both, so those sounds survive the vocoder instead of vanishing.
Choosing the notes
Carrier Source, the switch above the keyboard, decides what plays the carrier:
- Keys: the notes you play, from the on-screen keyboard or a MIDI keyboard. You need both: voice without notes, or notes without voice, is silent.
- Auto: the carrier plays your voice's own pitch, snapped to the Auto Key and Auto Scale you choose, so a plain vocal take vocodes with no MIDI at all. Harmony adds an octave, a fifth, a power chord or a triad, always on notes of the scale. Retune Speed sets how quickly the carrier moves to each new note; at zero it snaps. Unvoiced decides whether the last note holds through consonants and pauses or is released. Auto picks the carrier's notes; it does not retune the voice itself.
- Auto + Keys: held keys play the carrier; when you let go, your voice's pitch takes over again.
