Does changing speed affect audio quality?

Pitch-preserve mode re-encodes the audio, so there is a small quality reduction. At speeds between 0.5x and 2x this is minimal. Extreme speeds may introduce slight artifacts.

Can I speed up audio without changing the pitch?

Yes. Enable the pitch-preserve option (on by default). This uses FFmpeg's atempo filter which changes tempo without affecting pitch.

What is the maximum speed change?

The slider goes from 0.25x to 4x. Speeds above 2x or below 0.5x chain two atempo passes to stay within FFmpeg's filter limits.

Are my files uploaded to a server?

No. All processing runs in your browser using WebAssembly. Your files never leave your device.

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Audio Speed Changer Online Free

Speed up or slow down any audio file from 0.25x to 4x in your browser. The pitch-preserve option uses FFmpeg's atempo filter so speech stays natural and music stays in tune. Works with MP3, WAV, FLAC, OGG, M4A, and AAC. Your files never leave your device.