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Separation Strategy

Flags: --separate-missing, --reseparate, --separator

Suno provides stems, but sometimes they're incomplete or low quality. AI stem separation (Demucs, UVR) can generate alternatives from the full mix.

Decisions involved

  • Run separation at all? Only needed if stems are missing, damaged, or have too much bleed. The automatic pipeline skips this unless you pass --separate-missing.
  • Demucs vs UVR? Demucs (Meta's model) is the default — good general-purpose separation. UVR (Ultimate Vocal Remover) can be better for vocal isolation specifically.
  • Targeted re-separation? Use --reseparate to re-run separation on the full mix or a specific stem (e.g. to isolate vocals from a bleed-heavy stem).
  • Lighter/faster model vs slower/better? Demucs htdemucs is the default balance. Heavier models take longer but produce cleaner stems.

When to use each flag

Flag Use case
--separate-missing First-time processing — generate stems that Suno didn't provide
--reseparate Re-run separation after changing settings or to try a different backend
--separator demucs General-purpose separation (default)
--separator uvr When you specifically need cleaner vocal isolation

Example

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# Generate missing stems with Demucs
suno-to-ableton process /path/to/my-song --separate-missing

# Re-run with UVR instead
suno-to-ableton reseparate /path/to/my-song --separator uvr

# Standalone separation
suno-to-ableton separate /path/to/my-song --separator demucs

Combining with stem quality judgment

Run --choose-stems after separation to automatically compare originals vs generated stems:

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suno-to-ableton process /path/to/my-song \
  --separate-missing \
  --choose-stems \
  --apply