Bohlen–Pierce · non-octave instrument
Tritave
A playable microtonal keyboard with no octaves. Its interval of equivalence is the tritave — the 3:1 twelfth — split into 13 equal steps of ≈146.3 cents. Built on odd harmonics, it can sound consonant, and it is allowed to sound dangerous.
Now sounding
Press Start, then play the keyboard rows.
Input modes
- Keyboard · on start — rows A‥; / Q‥Y
- MIDI · —
- Tap · SVG keys (secondary)
Tuning
- step ratio 1.088182
- 146.30 cents / step
- 13 steps = 3:1 tritave (exact)
- tonic 220 Hz
Big nodes are the 9-note Lambda mode; small nodes are the chromatic infill. Timbre is additive with strong odd partials (3rd, 5th, 7th, 9th) so BP’s real 3:5:7 consonance can lock — and its clusters genuinely bite. Refs: Heinz Bohlen (1978); Max Mathews & John Pierce; Xenharmonic Wiki, “Bohlen–Pierce scale.”