Stem Separation

Stem separation splits a mixed track into isolated sources — drums, bass, vocals, "other" instruments, and optionally piano and guitar. Use them to drive per-element visual layers or download them as WAV files.

How to extract stems

  1. Upload your audio in the Studio as usual.
  2. Open the Stem Separation panel on the right.
  3. Select which stems you want. Four stems (drums / bass / vocals / other) are included with Premium. Piano + Guitar are Pro-only.
  4. Confirm the Upload-Rights checkbox.
  5. Click Extract Stems and wait — usually 1-3 minutes.
  6. Play each stem or download the full set as a ZIP.

Why are Piano + Guitar Pro-only?

Piano and guitar separation is significantly harder than the standard drums / bass / vocals / other split. It requires a more expensive inference path on our GPU workers, so we've made it part of the Pro-Tier. Upgrade to Pro to unlock.

How long do stems stay available?

After the retention window, stem WAVs are deleted from storage. The job record itself is retained for billing / audit.

Copyright & Upload-Rights FAQ

Q: Can I upload any song I want?
A: Only songs you have rights to. This includes your own compositions, your own Suno-AI generations, and tracks released under permissive licenses (Creative Commons, public-domain) where the license permits derivative works.

Q: Can I extract stems from a commercial song I bought?
A: Buying a song grants a personal-listening license, not a right to create derivative works. Extracting stems for commercial or public use is typically not allowed without the rights-holder's permission.

Q: What happens if I upload something I shouldn't have?
A: Our system relies on the attestation checkbox you accepted — legally you represent that you have the rights. If a rights-holder files a DMCA / EU-DSA notice, we'll honor it and may suspend your account per ourTerms of Service.

Quotas

Troubleshooting

Why is my extraction taking longer than usual?

Most jobs complete in 1-3 minutes. Longer queues happen during peak hours (18:00 UTC or weekend evenings). VJ-Tier subscribers get priority routing.

The vocal stem sounds muffled

Some source material (heavy reverb, autotune, wet bus compression) separates less cleanly. This is a limitation of current-generation models across the industry, not a KOSMOVIZ bug.

Can I cancel a running job?

Yes — click the × on the progress toast. Your quota is refunded if the job was still queued.

Need more help?

Email support@kosmoviz.com. Attach the job-id (shown in the progress toast) so we can look it up.