Audio Speed Changer

There are two completely different ways to change how fast audio plays, and knowing which one you need saves a lot of frustration. The simple way — the one this tool uses — is resampling: play the samples back faster or slower, exactly like speeding up a tape. It's honest, predictable and mathematically clean. The catch is physics: faster playback means higher pitch, slower means lower pitch. A voice at 2× sounds like a chipmunk; at 0.5× it sounds like it's underwater. The fancy alternative is time-stretching, which changes tempo while holding pitch steady using heavy signal processing. That's what professional podcast apps do — and it's deliberately not what happens here, because time-stretching always involves trade-offs and artifacts that are harder to predict.

When tape-style speed change is exactly right

For learning, tape-style is often better. Slowing a guitar solo to 0.75× or 0.5× drops the pitch too, which actually helps: the notes spread out in both time and frequency, making fast passages easier to pick apart by ear. Language learners slow down native speech to catch individual sounds; the lower pitch is a small price for the clarity. Speeding up works the other way: podcast and audiobook listeners routinely use 1.25×–1.5× to get through content faster, and a slightly higher voice is easy to ignore once you're used to it. Transcribers slow interviews to 0.8× so their typing can keep up.

Choosing your speed

A few battle-tested starting points: 1.25× for podcasts and lectures (noticeably faster, still natural), 1.5× for dense audiobooks you want to power through, 0.8× for transcription, 0.75× for learning a fast musical passage, 0.5× for forensic listening — figuring out exactly what was said in a mumbled recording. Small steps matter more than you'd think: the difference between 1× and 1.15× is barely noticeable, while 1.5× versus 1.75× feels like a different speaker entirely. Use the preview button liberally; it's instant and costs nothing.

About the WAV download

The download is a standard 16-bit WAV at your file's original sample rate — lossless, universally compatible, and encoded entirely on your device with plain JavaScript (which is why there's no MP3 option: MP3 encoding needs a heavy library). If you need a smaller file for sharing, convert the WAV to MP3 in any free converter afterwards. Keep the WAV as your master: every MP3 re-save throws away a little more quality, while WAV stays bit-perfect forever.