Correct overstated claims about the wall term and the junction fix (comments and sources doc): under 1 dB holds for f0 only (200/300 Hz harmonics +1.5 dB on one open vowel), the closed-tract bar is a second-order roll-off about 25 dB down above 300 Hz, back-vowel F1 error restated from Burg LPC

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docs/research/articulatory-vocal-tract-sources.md

@@ -63,7 +63,10 @@ it summed the areas of oral cells 11 and 12 and used their reflection coefficien
 pharynx (cells 10-12 of /o/: .52 .33 .52 cm^2) carried the next step's reflection with the wrong sign. Isolated by running the lip wave of the rendered
 ladder under an impulse against the numpy copy (the first echo already differed: -0.30 against -0.23), with the velum shut. Fixed, the render agrees
 with the numpy ladder to 10 Hz (o 520/830, uh 580/840, ah 690/980, aw 550/720, oo_short 500/920, u 290/820 at the harmonic lines) and the five tests
-run. The rest of the high reading against the tube chain (F1 +1.5 to +9%, F2 +2 to +8%) is the two radiation models' disagreement above.
+run. Read by Burg LPC on the renders (Soul pass of 2026-11-09), F1 error against the tube chain fell from 5c32bf6 to the fix 05efdc9 as uh +5.3 to -0.5, ah +2.5 to -4.3,
+aw +4.2 to +0.7, o +16.7 to +5.7, oo_short +12.7 to +4.9 percent: +2.5..+16.7 high before, -4.3..+5.9 after, the +5.9 being u, which the fix did not change (ah now
+undershoots by 4.3). The earlier "12-26 percent high becomes 1.5-9 percent high" came from the harmonic-line picker, not from LPC. What remains against the tube chain
+(F1 +1.5 to +9%, F2 +2 to +8% at the harmonic lines) is the two radiation models' disagreement above.
 
 Burg LPC (`burg_formants.py`) on the WordRender renders at 140 Hz (held vowels): /i/ in nibu 279/2105/2924, /u/ in nibu 283/836/2637, /ih/ in bin
 359/2012/2536, /oo_short/ (bʊn) in bun 543/899/2781, against the tube chain i 251/2063/2877, u 271/761/2574, ih 346/1987/2491, oo_short 478/850/2760 and
@@ -118,7 +121,7 @@ changes the level by -1.3 to +1.8 dB by vowel, so a single vowel is a noisy meas
 
 Plosive: word-initial /b/ closure is the tract wall's voice bar, -29.2 dB re the following vowel, /p/ -40.1 dB (`PlosiveClosureCarriesTheVoiceBarOnlyWhenVoiced`); /bɪn/ closure peak 0.0036 (was 0.0000, below 16-bit
 resolution), release 60-95 ms peak 0.0695, vowel 0.129. The wall radiation reads the first-cell pressure of the ladder (R0 + L0), band-limits it to 90-300 Hz and adds it at gain 0.7 (a DESIGN value for a voice-bar
-level of -30 dB; the primary level was not retrieved, and the 2.4 manual's skin radiation, Birkholz & Zhang 2025, is the reference to read). In a vowel the term moves the f0 harmonics by under 1 dB. The burst
+level of -30 dB; the primary level was not retrieved, and the 2.4 manual's skin radiation, Birkholz & Zhang 2025, is the reference to read). In a vowel the term moves the f0 line by under 1 dB; the 200 and 300 Hz harmonics move up to +1.5 dB on one open vowel (wall-only measurement, Soul pass). The band is two second-order sections, not a brick wall: with the mouth and the velum shut the bar sits about 25 dB down above 300 Hz. The burst
 itself (difference of renders with and without `release_flow`) peaks at about 0.006-0.008, -24 dB re the vowel peak; the release peak in the table above is the voicing breaking through as the contact opens. Burst gain 0.06 is a DESIGN VALUE.
 
 Weak spots found in the renders: (1) the vowel level is not steady, it rises for about 100 ms after onset (ɑ: rms 0.028 at 80 ms to 0.079 at 160 ms) so any window early in a vowel

src/AquaSynth.Core/FaustExport.cs

@@ -813,8 +813,10 @@ public static partial class FaustEmitter
 
     // Tract wall radiation (the voice bar). Corners: skin and soft tissue pass only the low end of the voice (below about 200-300 Hz), and
     // a second-order highpass at 90 Hz keeps the slow pressure drift of a shutting tract out (a 40 Hz first-order corner left it in). The gain
-    // is a DESIGN VALUE set so a word-initial voiced closure reads 30 dB under the following vowel (/p/ 41 dB), while the wall term moves a
-    // vowel's f0 harmonics by under 1 dB (no primary level retrieved; docs/research/articulatory-vocal-tract-sources.md).
+    // is a DESIGN VALUE set so a word-initial voiced closure reads 30 dB under the following vowel (/p/ 41 dB); the wall term moves a
+    // vowel's f0 line by under 1 dB and its 200 and 300 Hz harmonics by up to 1.5 dB on one open vowel (no primary level retrieved;
+    // docs/research/articulatory-vocal-tract-sources.md). Both corners are second-order sections: the closed-tract bar is about 25 dB down
+    // above 300 Hz, not cut off there.
     private const string WallRadiationHighpassHz = "90.0";
     private const string WallRadiationLowpassHz = "300.0";
     private const string WallRadiationGain = "0.7";