diff --git a/docs/re/audio-capture-alsa-file-tee.md b/docs/re/audio-capture-alsa-file-tee.md
index f41ef21a..64842ef1 100644
--- a/docs/re/audio-capture-alsa-file-tee.md
+++ b/docs/re/audio-capture-alsa-file-tee.md
@@ -131,6 +131,45 @@ clean capture.** At 9.98 % / 8.37 gaps/s it sits right on the port's "≥10 %
 silent *and* ≥1 gap/s" fail bar. **Do not treat it as an oracle without saying
 which side of that line it fell on.**
 
+## ✅ SOLVED — `--gpu=null` removes the residual, and the capture is clean
+
+The residual padding was the guest running at **0.70× real time**, and the
+dominant load is **llvmpipe software rendering** — which an *audio* capture does
+not need at all.
+
+| configuration | silence | gaps/s |
+|---|---|---|
+| PulseAudio monitor, xenia default | 39.3 % | 30.5 |
+| ALSA tee → paced slave, rendered (llvmpipe) | 9.98 % | 8.37 |
+| **ALSA tee → paced slave, `--gpu=null`** | **0.31 %** | **0.01** |
+
+**One gap in 67.7 s.** Six distinct channels, no duplicates, peaks −5.15 / −4.55
+/ −4.47 / −11.65 / −6.73 / −6.40 dBFS. For scale, the port's *genuine music bed*
+control measures 1.1 % silence at 3.3 gaps/s — **this capture is cleaner than
+their known-good reference.**
+
+✅ **Control that the run is still comparable:** `ADV`'s three XMA contexts
+(1 294 336 / 1 118 208 / 1 171 456) appear in the `--gpu=null` log, so the
+movie's voice is decoding exactly as in a rendered boot. That is also better
+provenance for an *audio* question than screenshots were — it evidences the thing
+being recorded rather than what was on screen.
+
+### The full working recipe
+
+```bash
+MAP=front-left,front-right,front-center,lfe,rear-left,rear-right
+pactl load-module module-null-sink sink_name=cap channels=6 channel_map=$MAP
+# asound.conf: NO include; tee in front of a PACED slave
+#   pcm.!default { type file  slave.pcm { type pulse }  file "…"  format raw }
+ALSA_CONFIG_PATH=…/asound.conf PULSE_SINK=cap \
+  run-canary --apu=alsa --mute=false --gpu=null …
+ffmpeg -f f32le -ar 48000 -ac 6 -i capture.raw out.wav      # float32, not s16
+```
+
+⚠️ `--gpu=null` means **no video**, so screen-based provenance is unavailable —
+use the XMA probe instead. And it is only appropriate when the question is about
+audio; it changes what the guest is doing.
+
 ## Consequences for verification
 
 🔴 **Short file becomes the failure mode**, so a capture check needs an