How to use it
- Open a stereo song (MP3, M4A, WAV, FLAC…).
- Keep "Keep bass and kick" ticked so the low end survives.
- Press "Remove centre vocals" and listen.
- Download your karaoke track.
What to expect
Centre cancellation removes anything panned to the middle, which usually means the lead vocal, but also the snare, bass and kick in many mixes (the bass option puts the lows back). Reverb on the vocal is often stereo, so a faint ghost of the voice can remain. Mono files cannot be processed because both channels are identical.
AI stem separators get cleaner results, but they need large neural models that would mean uploading your song. This tool keeps everything on your device and is instant.
Why subtracting one channel from the other removes the singer
A voice mixed dead centre is the same waveform in both speakers. A guitar panned left is much louder on the left. Subtract right from left, and identical signals cancel to zero while off-centre instruments survive. Move the singer to see the trick fail.
Left channel (voice + guitar)
Right channel (voice + a little guitar)
Left − Right = the karaoke track
Voice left in the result: 0%
That is also why the bass disappears: it is usually centred too. The "keep bass" option adds back the part of the centre signal below 150 Hz.
Questions
Is my audio uploaded anywhere?
No. The file is decoded, processed and encoded by your own browser using the Web Audio API. Nothing is sent to a server, which is also why it works on large files without a queue.
Why is there still some voice left?
Stereo reverb, doubled vocals and backing harmonies are panned off-centre, so they do not cancel. Songs with a dry, single lead vocal work best.
Can I extract only the vocals (acapella)?
Not with centre cancellation. Isolating the vocal needs a stem-separation model, which this private, offline tool does not use.