App Phasing Improvements

CLAUDE.md

@@ -78,6 +78,22 @@ The apparent "ceiling height" (floor-to-ceiling clearance) decreases toward the
 - Floor-to-ceiling behind last corner row: **2,950mm**
 - This is a structural change, not a continuation of the main flat ceiling
 
+**Corner geometry — 45° chamfer:**
+
+- The building corners are cut at 45° behind the last corner seating row
+- The perimeter wall in each corner is not a right-angle but a diagonal plane at 45° to the two adjacent side walls
+- This means corner listeners face the hall centre across the chamfered geometry, not across a square corner
+- Acoustic implication: the 45° angled surface redirects reflections diagonally inward rather than straight back — less flutter risk than a 90° corner, but creates oblique reflections toward the main seating zone
+- The geometry code currently approximates corner rows by radial position only; the 45° chamfer is not yet explicitly modelled in plan view
+
+**Corner staging void (HVAC):**
+
+- Below the corner seating there is a structural void — the corner seating is raised staging
+- This void is used as a plenum/duct for the HVAC ventilation system
+- The surfaces of this void (floor and underside of staging) are insulated to reduce sound transmission into and out of the ventilation path
+- Acoustic implication: the insulation damps what would otherwise be hard reflective surfaces; effectively the corner underfloor is acoustically treated
+- HVAC noise ingress from this void into the seating area is a risk factor — any REW measurement showing low-frequency noise floor elevation in the corner zone should be investigated against HVAC operating state
+
 **Ear height above local floor:** 1,100mm (seated listener, consistent throughout)
 
 **Ceiling tile grid:** 600mm × 600mm acoustic tiles — constrains speaker positions to 600mm increments from the grid
@@ -263,7 +279,12 @@ dishRise: 700,          // floor rise from centre to row 8 back face
 - Endpoint: `POST https://api.anthropic.com/v1/messages`
 - Default model: claude-sonnet-4-20250514
 
-**Analysis prompt:** Sends complete hall geometry, per-row coverage data (slant, delay, Haas, off-axis, SPL), flutter echo analysis, and optional REW frequency data. Requests structured sections: hall assessment, coverage issues, speaker position optimisation, Haas/delay analysis, anti-phasing assessment, MR12 EQ recommendations, ARTA measurement protocol.
+**Analysis prompt:**
+Sends complete hall geometry, per-row coverage data (slant, delay, Haas, off-axis, SPL), flutter echo analysis, and optional REW frequency data. Requests structured sections: hall assessment, coverage issues, speaker position optimisation, Haas/delay analysis, anti-phasing assessment, MR12 EQ recommendations, ARTA measurement protocol.
+
+
+**Analysis prompt:**
+You are an expert acoustic consultant specialising in distributed ceiling speaker systems for large assembly halls. You have deep knowledge of the accoustic ceiling speaker layout and design, including the MS6 speaker (Visaton FRS8M + G20SC drivers), the MIDAS MR12 active crossover with its 433 Hz gap at 3 kHz, anti-phasing techniques, and the Haas effect in multi-speaker environments. Analyse the provided coverage data and give specific, technical, actionable recommendations.
 
 ---
 

src/App.jsx

@@ -336,10 +336,12 @@ function SpeakerTab({ hall, speakers, setSpeakers }) {
             <Field label="Drop Rod Length" sub="0 = flush with ceiling"><NumIn value={spk.dropRod} onChange={v => set('dropRod', Math.max(0, v))} unit="mm" /></Field>
             <Field label="Power per speaker"><NumIn value={spk.power} onChange={v => set('power', v)} step={0.5} unit="W" /></Field>
             <Field label="Sensitivity" sub="dB / 1 W / 1 m"><NumIn value={spk.sensitivity} onChange={v => set('sensitivity', v)} unit="dB" /></Field>
-            <Field label="Phase">
+            <Field label="Anti-phase wiring" sub="Null lines form at segment boundaries — listeners hear only their nearest speaker">
               <select value={spk.phase} onChange={e => set('phase', +e.target.value)} style={{ ...numStyle }}>
-                <option value={1}>Normal (+)</option>
-                <option value={-1}>Anti-phase (−)</option>
+                <option value={4}>¼ Quadrant — pairs of 2 reversed (4 null lines)</option>
+                <option value={8}>⅛ Per-speaker — each speaker reversed (8 null lines)</option>
+                <option value={1}>All normal — no anti-phasing</option>
+                <option value={-1}>All inverted — entire ring reversed</option>
               </select>
             </Field>
             <Field label="Speaker Acoustic Centre" sub={spk.dropRod === 0 ? 'Flush ceiling ✓' : `${spk.dropRod} mm drop rod`}>
@@ -558,7 +560,7 @@ function AnalysisTab({ hall, speakers, settings, addLog }) {
 - Max rated coverage: 55° off-axis (near-circular polar response to 55°)
 - Sensitivity: 88 dB / 1 W / 1 m
 ${Object.entries(speakers).filter(([, v]) => v.enabled).map(([k, v]) =>
-  `- ${v.label}: ${v.count}× at r = ${v.radius} mm flush, ${v.power} W/spk (${(v.power * v.count).toFixed(1)} W total), phase ${v.phase > 0 ? 'normal' : 'anti-phase'}`
+  `- ${v.label}: ${v.count}× at r = ${v.radius} mm flush, ${v.power} W/spk (${(v.power * v.count).toFixed(1)} W total), wiring: ${{ 4: '1/4 quadrant anti-phase (pairs of 2 reversed, 4 null lines at aisle centrelines)', 8: '1/8 per-speaker anti-phase (each speaker reversed, 8 null lines)', 1: 'all normal (no anti-phasing)', '-1': 'all inverted' }[v.phase] ?? 'unknown'}`
 ).join('\n')}
 - Total installed power: ${Object.values(speakers).filter(v => v.enabled).reduce((s, v) => s + v.power * v.count, 0).toFixed(1)} W
 

src/constants.js

@@ -64,7 +64,8 @@ export const SPEAKER_DEFAULTS = {
     dropRod:        0,   // mm — flush (no rod)
     power:          6,   // W
     sensitivity:   88,   // dB / 1 W / 1 m  (Visaton FRS8M + G20SC combined)
-    phase:          1,   // +1 normal, -1 anti-phase
+    // phase codes: 1=all-normal, 4=quarter (quadrant), 8=eighth (per-speaker), -1=all-inverted
+    phase:          1,   // single speaker — no alternating pattern applies
     label: 'Centre (×1)',
   },
   inner: {
@@ -74,7 +75,7 @@ export const SPEAKER_DEFAULTS = {
     dropRod:        0,
     power:          8,   // W
     sensitivity:   88,
-    phase:          1,
+    phase:          4,   // 1/4 quadrant anti-phase (pairs of 2 reversed, 4 null lines)
     label: 'Inner Ring (×8)',
   },
   outer: {
@@ -84,7 +85,7 @@ export const SPEAKER_DEFAULTS = {
     dropRod:        0,
     power:          4,   // W
     sensitivity:   88,
-    phase:          1,
+    phase:          4,   // 1/4 quadrant anti-phase
     label: 'Outer Ring (×8)',
   },
   corner: {
@@ -94,7 +95,7 @@ export const SPEAKER_DEFAULTS = {
     dropRod:        0,
     power:          4,   // W
     sensitivity:   88,
-    phase:          1,
+    phase:          4,   // 1/4 quadrant (adjacent corners alternate, 2 spk per corner)
     label: 'Corner (×8, 2/corner)',
   },
 };