By Team Hypomnema · Updated October 19, 2026
Speed up or slow down recordings with linked pitch, semitone presets, reverse playback and MP3 or WAV export.
Prepare and preview
Add a recording and select the section to export.
Set speed or a linked semitone preset; enable reverse if needed. Speed and pitch change together.
Check the output duration, prepare the preview and download MP3 or WAV.
Limits and output quality
Browser-supported MP3, WAV, M4A, AAC, OGG, FLAC and WebM inputs; mono or stereo only. One file up to 20 MB and two minutes of source audio. Output is limited to two minutes. Processing stays local at 44.1 kHz in a cancellable worker. WAV is 16-bit PCM. MP3 re-encoding is lossy, can add frame padding and may use a lower sample rate at low bitrates. Export metadata is not preserved. The encoder reduces gain when necessary to prevent sample clipping. Speed and pitch are linked resampling controls: 2× is one octave higher and 0.5× is one octave lower. Independent pitch shifting and pitch-preserving tempo changes are not offered. A windowed-sinc filter reduces resampling artifacts; processed audio can still sound different. Slowing down increases duration; trim the selection if output exceeds two minutes. Reverse changes playback direction after speed processing. Semitone values reflect the actual speed ratio.
Try the workflow
Keep your original documents and review the output. You can also browse all guides or contact Team Hypomnema.