Audio Speed & Pitch

Audio Speed & Pitch changes how fast a recording plays and how high it sounds, either separately or together. Slow a guitar solo to 0.75× and it stays in tune; play a lecture at 1.5× and the voice stays natural; move a backing track up two semitones to suit a singer without changing its tempo.

For independent changes it uses our own time-stretching (a method called WSOLA) that cuts the sound into short overlapping pieces and joins them where the waves line up, so there is no chipmunk effect and no clicks. Pitch shifts are a stretch followed by a careful high-quality resample. Choose “Together, like a record” for the classic vinyl effect, where faster also means higher, which is how nightcore and “slowed” edits are made. A light room reverb is there for slowed + reverb.

Press play and move the sliders: the live preview changes within a fraction of a second. When it sounds right, save it as MP3, M4A, OGG, WAV or FLAC. It all happens in your browser, so nothing is uploaded and there is no sign-up or watermark.

1. Press “Choose a file” or drop an audio or video file on the box. It is read into memory and the preview player appears.
2. Tap a preset such as “1.25× faster”, “Nightcore” or “Slowed + reverb”, or set the sliders yourself.
3. Choose “Separate” to change speed and pitch independently, or “Together, like a record” to tie them.
4. Press the round play button and adjust Speed, Pitch, Fine tune and Reverb while it plays. The position bar lets you jump to any part.
5. Pick a format under “Save as”, then press the Save button. The new length is shown, and you can listen to the saved file before downloading it.

• Speed from 0.5× to 2× in steps of 0.01, keeping the original pitch.
• Pitch from −12 to +12 semitones plus ±50 cents of fine tuning, keeping the original speed.
• Both at once, or linked like a record or tape (pitch follows speed).
• Presets: Normal, 0.75×, 1.25×, 1.5×, 2×, Nightcore, Slowed + reverb, Deeper voice and Higher voice.
• Live preview while you move the sliders, with play, pause and a position bar (Space plays and pauses).
• Optional room reverb, the same in the preview and in the saved file.
• Stereo stays stereo: both channels are cut at the same places, so the image doesn’t wander.
• Saves as MP3, M4A, OGG, WAV or FLAC, with the new length and size shown.

• For practising an instrument, 0.75× or 0.8× is a good place to start; below about 0.6× drums and sharp attacks start to sound doubled.
• Speech holds up well even at 2×. Dense music is happiest between 0.75× and 1.5×.
• One semitone is one key on a piano. Moving a song two semitones down often puts it within reach of a lower voice.
• For a nightcore edit, try 1.25× to 1.3× together, like a record. For slowed + reverb, about 0.85× with 30 to 40% reverb.
• The whole file is held in memory while you work, so very long recordings (over half an hour) are best done on a computer.