Blog

What we measured, what we can legally ship, and what the numbers mean.

• SI-SDR, and the alignment trap that breaks it

  Separated stems lag the input by 219 samples. Score without correcting for it and a working separator reads -13 dB.

  2026-09-03

• Why we ship two stems and not six

  We went looking for a commercial licence for Demucs and MDX23C's weights and found none. Here is what that leaves, and why we would rather say so.

  2026-09-02

• We benchmarked every stem separator we can legally ship

  Six commercially licensable models, 12 MUSDB18 tracks, median SI-SDR — and a 5 dB gap on vocals that changed our default model.

  2026-09-01