A vocal tract you play like a synth. A buzzing source, like vocal folds, drives a model of the throat and mouth that you reshape with tongue, lips and soft palate controls to sing vowels and slur consonants.
The idea
Speech is made by a tube, not by samples. Air sets the vocal folds buzzing, and the shape of the tract above them filters that buzz into the vowels and consonants we recognise. Mouth Synth models exactly that, in the lineage of Neil Thapen's Pink Trombone: a chain of short tube sections, each with its own width. Sound reflects wherever the width changes, and the resonances that survive are the formants you hear as a vowel.
Moving the tongue slides the tightest point of the tube forward and back and raises or lowers it, which is the whole difference between "aah", "eee" and "ooh". A separate constriction pinches the tube at one spot, near the teeth for an "s" or at the lips for an "f", and when it closes fully and opens again you hear the small pop of a "p" or a "t". Opening the soft palate lets sound through the nose for hums and the "m", "n" and "ng" family.
Controls
- Tongue: Tongue Pos (back to front), Tongue Height, and Motion, how fast the mouth moves between shapes, from slurred to articulate.
- Constriction: Constrict Pos (off at its lowest setting), Constrict (how tightly it closes) and Fricative (how much hiss it makes).
- Voice: Tenseness (pressed and buzzy down to breathy), Breath (a steady airflow so the tract sounds with no key held), Throat (darker or brighter source) and Nasal.
- Pitch: Glide between notes, Vibrato depth and Vib Rate.
- Drone: Always Voice, on by default, keeps the voice sounding with no key held, like a bagpipe drone you shape; Wobble adds slow random pitch drift.
- Space: a built-in Reverb with its Room size.
Voice mode is Mono Legato by default, so each note slides from the last. Monophonic retriggers each note, and Polyphonic plays up to two voices.
The large diagram shows the shape of the tract as it moves. Where the host offers camera tracking, your own mouth can drive it.
Getting started
Play Mouth Synth from a MIDI keyboard or the C3 to B4 pitch strip on the panel. Start with Open Aah or Bright Eee, then move Tongue Pos and Tongue Height while you hold a note. Breathy Whisper and Om Drone show the breathy and nasal ends of the instrument.
Mouth Synth has a single mono output. In Polyphonic mode the drone and breath belong to the first voice only.
