Change audio speed without changing the pitch
From 4× slower to 4× faster, with studio-grade time-stretching (Signalsmith) running right in your browser. Nothing is uploaded.
How it works
Drop your file
Any MP3, WAV, OGG or M4A. The waveform appears in seconds. No upload, no queue.
Set the speed
Select the clip and drag the Speed slider in the inspector (25% to 400%), then hit Apply. Live progress, cancel anytime.
Check and export
Undo to A/B against the original, then export as WAV or MP3.
Why Ressoara
Pitch stays put
Slowing a lecture to 0.75× or pushing a podcast to 1.5× keeps voices natural, with no chipmunk effect.
Studio-grade engine
Powered by Signalsmith Stretch (MIT), a modern polyphonic time-stretching algorithm, not a naive resampler.
Non-destructive
The retimed audio becomes a new source; your original stays intact and one Ctrl+Z restores it.
Frequently asked questions
Naive speed changes shift the pitch too (the chipmunk effect). Time-stretching keeps the pitch intact while changing duration, so voices and instruments stay natural.
Yes: the inspector has both sliders side by side. Set a speed and a pitch shift and apply them in one pass.
No. The time-stretching is computed on your own processor, so a long file is bounded by your machine rather than by someone else's queue. The original on disk is left untouched.