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.
Controls
- Carrier: Wave chooses a saw, a pulse (with Pulse Width) or a supersaw (with Detune). Noise blends in noise, for whispered sounds. Octave, Tune, Voice Mode (Poly, Mono or Legato) and Glide work as on a synth.
- Formant: Formant Shift and Formant Stretch move and spread the carrier's bands, making the voice deeper or brighter without changing the notes. Emphasis tilts the bands toward the lows or the highs, and Resonance makes them ring.
- Analysis: Bands chooses 8, 12 or 16 bands. Band Slope chooses Sharp, steeper bands and the default, or Soft. Attack and Release set how quickly the bands follow the voice, and Freeze holds the current vowel so held notes sustain it.
- U/V (unvoiced, the consonants): U/V Source, U/V Sensitivity and U/V Level set how consonants are detected and how loud they come through.
- Output: Width spreads the sound in stereo, Voice Leak lets a little of the dry voice through underneath, Gain trims the vocoded level and Mix blends it with the original. The band frequency ranges live under Advanced.
The band map at the top shows the voice's bands above and the carrier's below, with a line joining each pair. The lines follow the live levels and bend as you shift or stretch the formants, and you can drag the triangle handles to change each side's frequency range. Indicators show when audio and notes are arriving.
Getting started
Vocoder takes audio in, usually a voice: a microphone, a recording, or another module. In Keys mode it also needs notes. Start with Classic Robot, speak or sing, and hold a chord. Then try Tight Robot, Warm Choir, Telephone Robot, Bright Droid, Wide Air, Talkbox, Glide Lead, Whisper or Deep Monk. To skip the keyboard entirely, choose Auto Robot; Auto Harmony sings an in-scale triad from your voice and lets held keys take over.
