Retune any song to 432 Hz.
Pick a song from Files or your Music library, set a target frequency, and FourThirtyTwo writes you a retuned copy. The whole thing runs on your iPhone.
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Home screen -
A/B preview the result -
Batch convert & export
Features
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Pitch detection
An FFT estimates the track's reference pitch before retuning, so the result lands on the right note.
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Pick the target
432 Hz by default. Set it to 440, 444, or anything in between.
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A/B preview
Flip between the original and the retuned version while it plays.
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Batch convert
Drop in a whole album and it'll process and name the files for you.
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Files and Music library
Imports from the Files app or your Music library. Export goes through the share sheet.
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On-device
Built on AVFoundation and Accelerate. There's no server side to it.
Frequently Asked Questions
What's the deal with 432 Hz?
440 Hz is the modern standard for concert pitch. Some listeners prefer 432 Hz, which is slightly lower, for how it sounds. The app doesn't take a side; it just makes the conversion easy.
Does it work with DRM-protected songs?
No. iOS won't let any app modify DRM-locked tracks like Apple Music streams. Anything you actually own works: purchased downloads, your own recordings, files in the Files app, and Music library tracks that aren't DRM-locked.
Where do exported files go?
Wherever you pick. You can save back to the Files app, send through the share sheet, or open the result directly in another app.
Does the app collect any data?
No. There's no backend and no analytics SDK. See the privacy policy if you want the long version.
What audio formats are supported?
The usual ones iOS handles: MP3, AAC/M4A, WAV, AIFF, and CAF. You pick the output format at export time.