London-based Keith Baxter has developed an intriguing mouth-played instrument called the Zen Flute Mouth Theremin, which blends acoustics, electronics and expressive performance.
The instrument is a variant of the theremin, which uses a forced Helmholtz resonator, a feedback system with a basic microphone and speaker setup, with the resonator being the player’s mouth.
The resulting pitch, created through subtle jaw and tongue movements, is detected and used to drive a MIDI controller feeding an external synthesizer, with the instrument using MIDI Polyphonic Expression to create smooth pitch transitions.
Physically, it hosts a flat speaker and microphone beside each other at the player’s mouth, and is connected to a length of clear PVC pipe while a custom PCB inside hosts a mic preamp, audio power amp and a Teensy 4.1 chip.
A push-button is used to trigger note onset, while a joystick adjusts timbre and selects modes, with different instrument profiles that can be pre-programmed and toggled with a joystick click, each mapped to separate MIDI channels.
