Real-time Music Key & BPM Analyser Tool
Tap Start and play music nearby.
Click Start Listening, allow microphone access, and play music near your device. Analysis updates continuously while listening.
Audio Gain Input
Adjust gain input for the space you're capturing audio from.
Estimated Key
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—
Estimated Tempo
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BPM
Input level —
Chroma profile (relative energy per pitch class)
How it works
- Key: A 12-bin chroma vector is built from the FFT, then matched against Krumhansl-Schmuckler major/minor key profiles.
- BPM: A spectral-flux onset signal is collected over a few seconds, then autocorrelated to find the dominant period in the 60-180 BPM range.
- All processing happens locally in your browser. No audio is uploaded.