About PurrHz
PurrHz retunes any song to 528 Hz, 432 Hz, 639 Hz or 852 Hz, right in your web browser. It was built by the team behind RestoreMind, a YouTube channel for sound-therapy and mood music, because we wanted a converter that was private, free, and good enough to use on our own tracks.
What makes it different
- Private by design. Your audio is processed on your own device. It is never uploaded to us or anyone else.
- Musically accurate. PurrHz detects your song's real tuning, then shifts it by the smallest amount needed so a real note lands exactly on your target frequency, using studio-grade resampling, with no grit or fuzz.
- Lossless output. You get a full-quality WAV file with no added compression.
- Honest about the science. Many people find frequency-tuned music relaxing, and so do we. But the research on specific health effects is limited, and we don't make medical claims.
How it works
When you add a file, PurrHz reads its format and analyzes the notes to estimate its reference pitch (most modern music uses A = 440 Hz). It then retunes the track with a studio-grade (windowed-sinc) resampler, the same class of processing used in professional audio software. An optional Exact tempo mode adds a transient-aware time-stretch for when the length must not change. Shifts are always under half a semitone, so tracks still sound like themselves.
Contact
Questions, feedback, bug reports or partnership ideas? Use our contact form. We read everything and usually reply within a few days.