Speed a track up or slow it down while the pitch stays exactly where it was — ideal for learning a part by ear or tightening a recording.
The speed changer stretches or compresses a track in time while leaving its pitch exactly where it was. Slow a solo to half speed and it stays in key; speed a podcast up and nobody sounds cartoonish. That independence isn't free — tempo and pitch are physically the same knob on tape or vinyl, and separating them takes real time-stretching rather than simply playing the file faster.
It's the standard tool for learning a part by ear, drilling a passage slowly before bringing it back to tempo, tightening a spoken-word recording, or matching two tracks' tempos for a mix. Extreme stretches can smear transients — drums are the first place you'll hear it — so moderate changes hold up best. How pitch, speed and duration are related explains what's actually happening, and the BPM finder will tell you the tempo you're starting from.
Simply playing a track faster or slower also raises or lowers its pitch, like speeding up a record. This tool avoids that by combining two steps: it changes the playback rate to hit your target tempo, then applies a pitch shifter by the exact opposite amount to cancel the pitch change. The result is a track that's genuinely faster or slower while every note stays at its original pitch — done entirely with the browser's audio engine, on your device.
They're opposites. The Pitch Changer moves the key up or down while keeping the tempo the same. The Speed Changer keeps the pitch the same while changing the tempo. Use the Speed Changer to slow a track down for transcription or practice, or to speed up a podcast or audiobook; use the Pitch Changer to move a song into a different key.
You can set anywhere from 0.5× (half speed) to 2× (double speed). Moderate changes sound very clean; extreme stretches — especially strong slow-downs — can introduce a slight graininess, which is a normal tradeoff of real-time time-stretching. You can hear the result live before exporting, so you can find the most natural setting for your track.
Yes. The export renders the exact tempo you've set, using the same processing as the live preview, into a WAV or Opus file. Because the length changes with tempo, a slowed-down track produces a longer file and a sped-up track a shorter one — the estimated size shown next to each format reflects that.
No. Decoding, time-stretching, and export all run locally in your browser. Your file is never uploaded, and processing speed depends on your own device rather than a server queue.