The separation takes one upload. The part that decides whether you can actually play the result is everything after it.
Separation quality is capped by what you feed it. A lossless file or a 320 MP3 gives a noticeably cleaner vocal than a 128 rip, because the model cannot recover detail that was thrown away by the encoder. If you own the record in a lossless format, use that one.
Upload the track. The vocal and the instrumental come back as separate files, both lossless AIFF and MP3 320, both already carrying the key and the tempo. Credit is €0.10 per minute of the source and is only spent once the separation actually succeeds.
Vocals separate cleanly over sparse arrangements and badly over dense ones. An intro will flatter almost any tool. Skip to the busiest part of the record; that is where artefacts live, and that is where you will hear whether it is good enough to play.
This is the step most guides skip, and it is the one that decides whether the acapella is mixable. Do not analyse the separated vocal: with no kick and soft transients, beat trackers perform far worse on a bare vocal than on a full record. Take the key, the tempo and the downbeat from the original mix and apply them to the stem.
Here that happens automatically — both halves inherit the analysis of the full mix.
Serato stores its beatgrid inside the file's tags, so a properly tagged AIFF opens ready to play. Files that arrive untagged have to be analysed and often hand-gridded, per file, forever. See acapellas for Serato for the detail.
Start with a record you already play out. No account, no subscription — €0.10 per minute.
Open the toolNo. It runs in the browser — upload a track, download the stems. Nothing to install.
A few minutes for a full track, depending on its length and how many jobs are queued ahead of it. The page updates itself, so you do not have to sit on it.
Playing a bootleg you made from a record you own is between you and the venue. Releasing or monetising it needs clearance from the rights holders, the same as any sample.