Audio speed changer

Adapt the length of a lecture, spoken take or musical passage with a factor from 0.5× to 2×. Processing writes the change into a new file while aiming to preserve voice and note pitch. Use it to study rhythm or prepare faster listening without asking recipients to adjust their players. Check consonants and musical attacks before sharing.

The atempo filter changes playback speed without transposing musical pitch. At 2× the duration is roughly halved; at 0.5× it is roughly doubled. The range is intentionally limited to 0.5×–2× by the current shared-engine contract. The default 1× setting requests no tempo change but still creates a new 16-bit PCM WAV. The editor control advances in 0.05 steps from 0.5× to 2×. The filter renders a new signal rather than setting a player-only speed flag, so the downloaded file keeps the change. Preserving pitch does not prevent artifacts in consonants, reverberation or musical attacks. Dividing duration by speed gives a reference estimate: actual frame count depends on processing and the signal. Use pitch shifting instead when the intended change concerns musical height rather than length.