Vocal-presence proxy on the locked KNOTSLOP bed: 3 of 16 segments flagged
Hardware and Config
- Machine: Genesis box (Threadripper PRO 9975WX per purchase invoice; the check is CPU-side, no GPU used)
- OS: Windows 11
- Date: 2026-11-08
Software Versions
- Python 3.14 in the project venv (C:\rafiki-aos\work\audio-venv, locked in docs/audits/knotslop/VENV-LOCK.txt)
- numpy 2.5.4, soundfile 0.14.0, scipy 1.18.1
- Input: work\knotslop\bed-48k.wav (the S3 decode of the LOCKED KNOTSLOP bed opus-5-51.mp3, sha 2c4d27e3...8269; the original mp3 was never modified)
Raw Numbers
Spectral proxy: per 8-bar segment, mean STFT energy (1024 window, hop 256) in the formant band (1-4 kHz) vs the rhythm band (40-200 Hz), in dB. Flag = ratio above the bed's own median + 1.5 standard deviations.| Property | Value |
|---|---|
| Segments analyzed | 16 (8 bars each, 138 BPM) |
| Formant-ratio median | -26.0 dB |
| Standard deviation | 5.6 dB |
| Segments flagged | 3 (seg 1, 2, 7) |
| Flagged time ranges | 0-14 s, 14-28 s, 84-97 s |
| Seg | Bars | Time (s) | Formant (dB) | Rhythm (dB) | Ratio (dB) |
|---|---|---|---|---|---|
| 1 | 1-8 | 0-14 | -48.6 | -37.8 | -10.8 |
| 2 | 9-16 | 14-28 | -46.0 | -30.9 | -15.1 |
| 7 | 49-56 | 84-97 | -47.2 | -30.3 | -16.9 |
What the Numbers Do and Do Not Show
- DO show: which sections of the locked bed have formant-band energy well above the bed's own baseline - the cheapest possible listen-first shortlist
- DO NOT show: whether those sections contain actual vocals. Bright synths and leads also live in 1-4 kHz. This is a PROXY, not a separation (UVR5, the real separation tool, is 0% installed on GPU1)
- WHY IT MATTERS: the bed was generated with a hard "purely instrumental" directive but had no recorded vocal-presence verification. If a human ear hears vocals in any flagged range, the bed needs a UVR5 strip before the master is final; if the flagged sections are clearly instrumental leads, the verification closes with this check
AI Disclosure
This check was run and written by an AI agent (OpenCode Build for Danny) on the Genesis box. The audio venv is project-local; the locked bed was read, never modified.Link Slots
- Raw numbers: docs/recipes/raw/knotslop-bed-vocal-proxy-20261108.json (per-segment table)
- Source: work\knotslop\bed-48k.wav (decode; original opus-5-51.mp3 untouched, on the NAS)
- Rerun script: work\knotslop\bed_vocal_check.py (venv python: C:\rafiki-aos\work\audio-venv\Scripts\python.exe -I -B)
- Related posts: BEDDECODE-001 (the structure this check segments)