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🎹 Equal Temperament Explained

Interactive 3D piano keyboard and frequency wheel comparing just-intonation ratios against 12-tone equal temperament across an octave.

Acoustics2DEasy60 FPS

A 3D piano keyboard and a circular frequency wheel let you click through every note of an octave, hear it played in real time via the Web Audio API, and see exactly how far 12-tone equal temperament drifts from the pure whole-number ratios of just intonation.

🔬 What It Demonstrates

Equal temperament splits the octave into twelve identical ratio steps of 2^(1/12), while just intonation uses simple whole-number ratios like 3/2 and 5/4. The wheel's purple and teal bar heights, and the live cents readout, show precisely how much each note bends away from "pure" tuning.

🎮 How to Use

Pick a root note and concert pitch, then click any piano key or wheel bar to hear its frequency. Toggle the just-intonation overlay on or off, or press "Play scale" to step through the full octave in either tuning system.

💡 Did You Know?

Equal temperament's major third is roughly 14 cents sharper than the pure just-intonation third — audible enough that unaccompanied singers and string quartets naturally drift toward just ratios when there's no piano to keep them locked to the grid.

⚙ Under the hood

Interactive 3D piano keyboard and frequency wheel where comparing just-intonation ratios against 12-tone equal temperament lets users hear and see how each note's frequency is tuned across an octave.

equal-temperamentmusic-tuningjust-intonationmusic-theorysoundacoustics

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install