By Team Hypomnema · Updated October 19, 2026
Extract left or right, swap channels, mix mono, isolate mid or side, adjust stereo width and invert polarity.
Prepare and preview
Add a mono or stereo recording and optionally trim it.
Choose the output routing. For stereo output, adjust width and balance; invert input polarity if needed.
Prepare the preview, check both channels 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. Left, right, mid and side extraction export mono files. Mid and mono use (L + R) / 2; side uses (L − R) / 2. Centered sound cancels in side output, and opposite-polarity sound can cancel in mono. This is channel mathematics, not AI vocal isolation or source separation. Width and balance apply only to stereo and swapped-stereo output, after input polarity controls. Mono sources support Mono and Left only. Widening can raise peaks or reduce mono compatibility; peak protection may reduce overall gain.
Try the workflow
Keep your original documents and review the output. You can also browse all guides or contact Team Hypomnema.