Lightweight Music Source Separation — Listening Test

Vocals and accompaniment separated from a 44.1 kHz stereo mix by one model family at four sizes (1.35 – 5.7 MB deployed, INT8 weights). Accompaniment is the mixture minus the separated vocals, so a single model gives both stems. The clip is a 20 s excerpt (1:35 – 1:55) of Juliet's Rescue – Heartbeats from the MUSDB18-HQ test set, which was never used in training. Use headphones.

Objective evaluation

MUSDB18-HQ test set, all 50 songs. cSDR is the median of the 1 s chunk SDRs pooled over all songs. Offline inference uses 12 s windows with 75 % overlap. ↑ higher is better.

Size	Params	GMACs / 2 s audio	Size INT8	Vocals cSDR FP32	Vocals cSDR INT8 ↑
L	≈ 5.5 M	38.8	5.72 MB	10.95	10.93
M	≈ 4.2 M	31.6	4.42 MB	10.81	10.79
S	≈ 2.6 M	16.2	2.75 MB	9.95	9.94
XS	≈ 1.2 M	7.16	1.35 MB	9.13	9.13
DTTNet (public weights, re-scored)	≈ 5.0 M	–	4.97 MB	10.13	10.11

Vocals cSDR versus deployed model size for sizes L, M, S, XS and the DTTNet baseline — M keeps L's quality within 0.14 dB. XS keeps 9.13 dB at a quarter of the size.

Vocals cSDR versus analysis window length for sizes L and XS — Streaming: shorter windows give less musical context. A 2 s window is the knee for both sizes. Accompaniment as mixture − vocals scores 20.01 dB cSDR for L (INT8), higher than a dedicated accompaniment model.

Listening clips

Scores are cSDR against the reference stem: for the full song, and for the 20 s excerpt behind the players.

Vocals 20 s excerpt · 44.1 kHz stereo

Spectrograms: mixture, reference, sizes L, M, S, XS — Top to bottom: mixture · reference · L · M · S · XS (0–11 kHz, 80 dB range; cSDR in the labels is for the full song).

MixtureMUSDB18-HQ test set
LINT8 weights · ≈ 5.5 M params · 5.72 MBcSDR song 11.15 · excerpt 11.23 dB
MINT8 weights · ≈ 4.2 M params · 4.42 MBcSDR song 11.09 · excerpt 11.30 dB
SINT8 weights · ≈ 2.6 M params · 2.75 MBcSDR song 10.28 · excerpt 10.39 dB
XSINT8 weights · ≈ 1.2 M params · 1.35 MB · smallestcSDR song 9.69 · excerpt 10.16 dB
Reference vocalsreference stem

Accompaniment 20 s excerpt · 44.1 kHz stereo

MixtureMUSDB18-HQ test setcSDR as accompaniment: song 6.53 · excerpt 9.31 dB
LINT8 weights · ≈ 5.5 M params · 5.72 MBcSDR song 20.43 · excerpt 20.95 dB
MINT8 weights · ≈ 4.2 M params · 4.42 MBcSDR song 20.33 · excerpt 20.88 dB
SINT8 weights · ≈ 2.6 M params · 2.75 MBcSDR song 19.31 · excerpt 19.90 dB
XSINT8 weights · ≈ 1.2 M params · 1.35 MB · smallestcSDR song 18.65 · excerpt 19.11 dB
Reference accompanimentreference stem

Music excerpt: Juliet's Rescue – Heartbeats, MUSDB18-HQ test set (Rafii et al., 2019, doi:10.5281/zenodo.3338373), used for non-commercial research demonstration only; rights remain with the original artists. Tables: README.md and results/ in the repository.