What Is StemRoller and What Can It Do?

Updated

StemRoller is a free, open-source desktop app that splits any song into separate audio tracks — called stems — using AI. Type a song title into its search bar, and it finds the song online and separates it into four stems: vocals, drums, bass, and everything else. It also automatically creates an instrumental version (all non-vocal stems mixed into one track). It's built on Demucs, Facebook's state-of-the-art AI/machine learning research project.

What StemRoller produces

From a single song, StemRoller generates:

  • Vocals — the isolated vocal track
  • Drums — the isolated drum track
  • Bass — the isolated bass track
  • Everything else — all remaining instruments combined
  • Instrumental — a ready-made karaoke-style mix of every non-vocal stem

That five-file output covers the most common uses: karaoke backing tracks, acapella vocals, and individual parts for remixing or practice.

How it works

  1. Search — Type a song title into the search bar at the top of the app.
  2. Find — StemRoller locates the song online automatically.
  3. Split — One click runs the Demucs AI model, which separates the recording into the four stems listed above.
  4. Collect — You get the four stems plus the instrumental mixdown.

The whole point of the tool is that this happens in one click — you don't need to configure a model, install Python packages, or run command-line scripts yourself.

Who it's for

Use case What you'd use
Karaoke / singing along Instrumental track
Acapella or vocal remix Vocals stem
Practicing an instrument Drums, bass, or "everything else" stem
Remixing or sampling Any individual stem

Cost and licensing

StemRoller is totally free and open-source. The site lists a Donate option for people who want to support development, but the app itself carries no price. Because it's open source, its code and its dependencies (including Demucs) are publicly documented.

Getting help

If you run into an issue or have a question, the project points users to its Discord community for support.

Key things to know before you start

  • You need to download and install the app — it's a desktop application, not a browser tool.
  • It works from a song title, not a file you upload, so it looks the song up online for you.
  • Output is fixed at four stems plus an instrumental — it doesn't offer a custom number of splits.
  • The separation quality comes from Demucs, so results track the capabilities of that model.