Quick Answer
A music retuner shifts a recording’s pitch by the ratio between two reference pitches — 432 ÷ 440, about −31.77 cents. Drop in songs, pick a target reference, and this free tool plays and exports the retuned audio entirely in your browser: a resample engine (pitch and tempo move together) or a pitch-only engine that time-stretches back to keep the original tempo. Nothing is uploaded and no account is required.
How It Works
Add tracks: drop audio files onto the tracks panel or click to browse — MP3, WAV, OGG, M4A, and FLAC as your browser supports them
Set the references: keep the source at 440 Hz (or what your track was tuned to) and pick a target with the 432, 440, 444, or 528 Hz chips or a custom value
Choose an engine: Resample moves pitch and tempo together; Pitch-only time-stretches back so the tempo stays original
Preview: play one track at a time, scrub the position bar, loop, and adjust volume while the visualizer shows the spectrum
Export: download a verified 16-bit WAV per track, or use Export all to render the whole playlist sequentially
Key Facts
- Retune between any two reference pitches — 432, 440, 444, 528 Hz chips or custom values
- Cents shift is computed exactly as 1200 × log2(target ÷ source): 440 → 432 is −31.77 cents
- Resample engine shifts pitch and tempo together with no artifacts beyond the rate change
- Pitch-only engine adds a WSOLA time-stretch (2048-sample grains, ±256-sample search) that preserves tempo
- Playlist handling for many files: decode, per-track status, play one at a time, scrub, loop, volume
- Live frequency-bar visualizer, with a static level meter when reduced motion is preferred
- Export any track — or all of them sequentially — as 16-bit PCM WAV at the original sample rate
- Every export is verified by decoding it back with the browser audio engine before it downloads
- Free, no account, and both engines process locally — files never leave your device
Frequently Asked Questions
How does the 440 to 432 Hz conversion work?
The tool treats a reference change as a ratio: 432 ÷ 440 = 0.981818. Resampling the audio by that ratio lowers every note by 1200 × log2(432 ÷ 440) ≈ −31.77 cents, the exact interval between the two tuning references. The same math applies to any pair of references, including 444 Hz (+15.67 cents) or 528 Hz (+315.64 cents).
What is the difference between the two retune engines?
The resample engine plays the file at the reference ratio, so pitch and tempo move together — at 432 Hz the track is also about 1.82% slower, with no processing artifacts. The pitch-only engine resamples and then time-stretches the audio back with a WSOLA algorithm (2048-sample grains, ±256-sample alignment search), so the tempo stays original; this basic time-stretch can add slight artifacts on transients like drum hits.
Is my music uploaded anywhere?
No. Both engines run locally in your browser using the Web Audio API and plain JavaScript DSP. Files never leave your device, nothing is sent to a server, and the only thing saved is your retune settings in this browser’s local storage.
Is it free, and how does it compare to paid retuning apps?
Fully free with no account. Paid options exist — for example HZP, a dedicated 432 Hz player, or pitch plugins for DAWs — which add music-library management and batch workflows. For retuning a few files, previewing them, and exporting WAV, this page does the whole job at no cost.
Which audio formats can I load?
Anything your browser can decode: typically MP3, WAV, Ogg Vorbis, M4A/AAC, and often FLAC — exact support differs between Chrome, Edge, Firefox, and Safari. Decoding happens locally, and a file the browser cannot decode simply shows an error row you can remove.
What do I get when I export?
A 16-bit PCM WAV file at the track’s original sample rate and channel count, named with the target reference (for example, song-retuned-432hz.wav). Each export is decoded back and verified before download, and Export all renders tracks one by one with a progress count.