Double speed
A 60-second clip at 2× becomes about 30 seconds long. Frequencies double, raising the pitch by one octave or 12 semitones.
WAV, MP3, Ogg, M4A and other inputs depend on browser codec support. No file is uploaded. Output is always WAV.
Your inputs and generated files are processed locally in your browser. No input is uploaded to an audio or text-processing service.
How to use the Audio Speed Changer
- 01
Choose a mono or stereo clip under 20 MiB and at most 120 seconds long.
- 02
Set a speed between 0.5 and 2 times the original. Review the resulting duration and pitch shift.
- 03
Preview the changed audio and download a 16-bit PCM WAV if it fits your purpose.
Examples
Three-quarter speed
A 30-second phrase at 0.75× becomes about 40 seconds long. The pitch moves down approximately 4.98 semitones.
Duration follows the rate ratio
Output duration is the original duration divided by the speed multiplier, with rounding to whole sample frames. The displayed pitch change is 12 × log2(rate), measured in semitones.
This changes pitch as well as timing
The implementation reads source samples at a different rate and uses linear interpolation between neighboring frames. It does not separate timing from pitch. Voices sound lower when slowed and higher when accelerated.
Preview, quality, and file format
Preview plays the same resampled data used for export. The WAV keeps the decoded sample rate and mono/stereo layout, using 16-bit PCM. Linear interpolation is useful for simple experiments but is not a high-quality antialiasing resampler or a mastering tool.
What to know
- 0.5–2× speed, 20 MiB input, 120-second mono/stereo sources.
- Pitch changes with speed. Linear interpolation can introduce artifacts, especially when speeding up.
Common questions
Can I slow music without changing the key?
No. Pitch-preserving time stretching requires a different algorithm. This tool deliberately changes pitch with speed.
Does it download the original file format?
No. MP3, M4A, Ogg, and other supported inputs are decoded, processed, and exported as actual PCM WAV audio.
How long can the output become?
The input is limited to 120 seconds. At the minimum speed of 0.5×, the output is about 240 seconds. A 24-million-sample export bound also protects memory.
Will tags and cover art be preserved?
No. The generated WAV contains its audio format and PCM samples; original metadata and artwork are excluded.