Audio Tempo Changer Online

or drop files here

Change musical tempo while retaining the original pitch with overlap-add time stretching. Waveform-similarity overlap-add aligns short audio windows before blending them. Moderate ratios work best; complex mixes and strong transients may develop artifacts.

Calculate a practice tempo

Divide the desired BPM by the original BPM. To rehearse a 120 BPM phrase at 90 BPM, choose 90 ÷ 120 = 0.75; a sixty-second phrase then lasts about eighty seconds.

Preserve pitch through window alignment

Waveform-similarity overlap-add searches neighboring samples for matching window boundaries. It repeats or removes short regions while attempting to maintain local oscillation periods and shared stereo alignment.

Evaluate transient detail

Listen to kick attacks, claps and consonants after a large tempo change. Extreme stretching can smear attacks or produce a repeating texture even when the fundamental musical key is retained.

Wait for the refreshed rendition

Changing the multiplier schedules a new worker render. The player receives the completed version automatically; this is background preview generation rather than a zero-latency streaming time-stretcher.

Technical references: Web Audio API specification

Audio Tempo Changer FAQs

Audio Tempo Changer decodes and processes the selected audio in your browser. File contents are not sent to an audio-processing server; page analytics are described in the site privacy policy.
Audio Tempo Changer saves 16-bit PCM WAV. MP3, WAV and other browser-supported inputs are decoded first; WAV output cannot restore detail lost in a compressed source.
Open Audio Tempo Changer, choose your recording, adjust its settings and compare the preview before rendering a WAV download. This page refreshes its preview after a background render.
Audio Tempo Changer schedules a background render after a setting changes. The completed preview or analysis replaces the previous result automatically. Processing time depends on recording length and device performance; the status message shows when the new result is ready.