The Sonimba is a kalimba rebuilt with pickups, sensors and real-time audio processing.
The build
- The kalimba
- It started as an ordinary kalimba, which was taken apart and put together again in a new form.
- Pickups: a custom pickup system captures the metal tines. The signal goes into an embedded DSP platform built on Bela.io.
- Sensors and controls
- IMU sensor: an Adafruit BNO055 tracks orientation and acceleration in three dimensions, so tilting, rotating and shaking the instrument changes the sound.
- Trill bar: a touch sensor that tracks up to five fingers, each one its own control point.
- Potentiometers: for effect amount, layer blend and modulation speed.
- Pushbuttons: for loops, effects and the reversers.
Audio processing
- Looper
- Records, overdubs and plays back, controlled with the pushbuttons.
- Granular engine
- Captures live audio into a buffer.
- Each finger on the trill bar is an independent playhead that scrubs through the buffer.
- The IMU controls grain size, playback speed, pitch and jitter.
- Effects
- Saturation and bitcrush, distortion, filters, tape-delay emulation, flanger, phaser, chorus and reverb.
- Reversers
- Incoming audio is recorded continuously, so it can be played backwards at any moment.
- The reversed audio can be pitch-shifted. Octaves work best.
Parameter space
- Setting it up
- The parameters for effects and granular synthesis are adjusted from a computer via Open Sound Control (OSC).
- Tilt to save
- When a setting sounds good, the Sonimba is tilted to any position and the setting is saved there as a preset.
- This builds a landscape of presets, each tied to an orientation of the instrument.
- Playing it
- While playing, the IMU tracks the orientation and the sound interpolates between the saved presets, so it changes smoothly as the instrument is tilted or rotated.