How it works
Add your track
Pick any song on your device. It loads into your browser's memory and is never uploaded.
We retune it
Every note shifts by the same small amount, so the nearest note lands exactly on your chosen frequency, using studio-grade resampling.
Download
Compare it with the original, then save a full-quality WAV you can play anywhere.
The frequencies
| Target | What changes | Shift |
|---|---|---|
| 528 Hz | C lands on 528 Hz (A ≈ 444 Hz) | +16 cents |
| 432 Hz | A lands on 432 Hz | −32 cents |
| 639 Hz | D♯ lands on 639 Hz (A ≈ 451.8 Hz) | +46 cents |
| 852 Hz | G♯ lands on 852 Hz (A ≈ 451.3 Hz) | +44 cents |
100 cents = one semitone. Every option stays under half a semitone, so songs still sound like themselves.
Frequently asked questions
What does "528 Hz" actually mean here?
Most modern music is tuned so the A above middle C is 440 Hz. PurrHz shifts the whole track by the smallest amount that puts a real note exactly on your target. For 528 Hz that's C, with A moving to about 444 Hz. Melody, harmony and rhythm stay intact.
How do 639 Hz and 852 Hz work?
Those frequencies fall between notes on a standard keyboard, so we nudge the track up until the nearest note (D♯ for 639, G♯ for 852) hits the target exactly. That's a shift of about 45 cents, a little under half a semitone.
Is my file uploaded anywhere?
No. Decoding, retuning and encoding all happen inside your browser with the Web Audio API. Nothing is sent to a server, and closing the tab clears it from memory.
What's the difference between "Pure pitch" and "Exact tempo"?
Pure pitch retunes the song the way a turntable would: it plays very slightly faster or slower, by 1–3%, with nothing stretched or processed, so it is the most transparent option. Most people can't notice the tempo change. Exact tempo uses a time-stretch engine to keep the original length to the sample. It's very clean too, and useful when a track has to sync with video or other audio.
What if my song isn't tuned to 440 Hz?
PurrHz checks for that automatically. When you add a file, it listens to the notes and estimates the song's real reference pitch, then calculates the shift from there. Very percussive, noisy or spoken tracks don't have clear enough notes to read, so for those we fall back to standard A = 440 Hz.
Do these frequencies have proven health benefits?
Honest answer: the research is thin. 528, 639 and 852 Hz are popular in sound-wellness communities, and many people find them relaxing, but there's limited scientific evidence for specific physical effects. Enjoy them for how they sound and feel. They aren't a substitute for medical care.
Why does my converted song sound fuzzy or muddy?
Almost always, it's the source file. Low-bitrate MP3s (under about 128 kbps), files ripped from streaming or video sites, and songs that have been re-compressed several times already contain compression artifacts like swishy cymbals, a dull top end, or a "watery" sound. PurrHz retunes the audio cleanly, but no converter can remove damage that's already baked in. When you add a file, the info panel flags low-quality sources. For the best results, start from a WAV, FLAC or high-bitrate MP3 (256–320 kbps).
Why is the download a WAV?
WAV is lossless, so it adds no extra quality loss on top of your original file. It's bigger than an MP3, about 10 MB per minute of stereo audio.