Demucs ships multiple model variants trading speed, quality, size, and stem count

Demucs includes a menu of pretrained models selectable with -n NAME. Key variants: htdemucs — Hybrid Transformer Demucs v4, default, 4 stems, best general quality; htdemucs_ft — per-source fine-tuned version, ~4× slower but slightly better; htdemucs_6s — adds guitar and piano stems; hdemucs_mmi — v3 Hybrid Demucs; mdx / mdx_extra — MDX competition models; mdx_q / mdx_extra_q — quantized models (smaller download, marginally lower quality). For practical sampling, htdemucs_ft gives the best stems; for fast batch processing, mdx_q trades quality for speed and storage.

Examples

demucs -n htdemucs_ft mytrack.mp3      # best quality, 4x slower
demucs -n htdemucs_6s mytrack.mp3      # try guitar/piano split
demucs -n mdx_q mytrack.mp3            # faster, smaller model

Assessment

Name three scenarios where you would choose mdx_q over htdemucs_ft, and explain the trade-off in each.