Acapella extractor. Pull the centre vocal out of a stereo song, free, in your browser. No sign-up.

In almost every mix the lead vocal is panned dead centre, so it is identical in the left and right channels, while guitars, keys, backing vocals and the reverb are spread across the stereo field. The free Vocal Remover uses that to cancel the centre. This tool does the opposite and keeps it.

Keeping the centre takes more than adding the two channels together, which only turns the sides down by half. The song is split into 1025 narrow frequency bands, about every 12 milliseconds, and in each band the tool compares the two channels: where they match in level and timing, the band is kept; where they differ, it is dropped. Below 120 Hz everything is dropped, since the bass and kick sit there and a voice carries little.

It keeps whatever is in the centre, not just the voice. The kick and snare, a centred bass's upper harmonics, a lead synth or a solo instrument panned centre all come through with the vocal. It loses what makes a vocal wide: stereo reverb and delay, double-tracking and harmonies panned left and right fade out, so the result is drier and narrower than the vocal in the mix.

On a sparse mix with a dry, centred vocal (a lot of pop, hip-hop and acoustic music) the result can be usable for a remix sketch or practice. On a dense mix it sounds like the vocal with the band's ghost behind it. A mono file is refused, because in mono everything is in the centre.

A separation model listens to the music rather than the panning, so it can pull the voice away from a centred snare or synth and keep the vocal's own reverb. In the SoundGen studio it splits a song into vocals, drums, bass and other instruments as separate tracks. A standard separation costs 6 credits, and new accounts start with 100 free credits.