melodic fine tuning

frontend/src/App.jsx

@@ -15,8 +15,8 @@ const KEY_VOTE_WINDOW    = 12
 const KEY_VOTE_THRESHOLD = 9   // out of 12 — very stable
 
 // Chord detection tuning
-const CHROMA_SMOOTH        = 8    // frames to average (~130ms at 60fps)
-const CHORD_VOTE_THRESHOLD = 3    // consecutive agreements before commit
+const CHROMA_SMOOTH        = 12   // frames to average (~200ms at 60fps)
+const CHORD_VOTE_THRESHOLD = 4    // consecutive identical detections required
 
 export default function App() {
   // ── Listening state ──────────────────────────────────────────────────────
@@ -33,7 +33,8 @@ export default function App() {
 
   // Effective key used by all components
   const effectiveKey = lockedKey ?? keyInfo
-  const isStrictMode = appMode === 'beginner' && lockedKey !== null
+  // Locked key = only match diatonic chords regardless of mode — far fewer candidates
+  const isStrictMode = lockedKey !== null
 
   // ── Chord state ───────────────────────────────────────────────────────────
   const [chordHistory, setChordHistory]             = useState([])
@@ -122,17 +123,19 @@ export default function App() {
     for (let i = 0; i < 12; i++) avg[i] /= CHROMA_SMOOTH
 
     const chord = matchChordFromChroma(avg, key, bassPC, isStrictMode)
-    if (!chord) return
+    if (!chord) {
+      // Ambiguous moment (transition, silence) — reset streak, history is untouched
+      chordVotesRef.current = []
+      return
+    }
 
     const votes = chordVotesRef.current
     votes.push(chord)
-    if (votes.length > CHORD_VOTE_THRESHOLD * 2) votes.shift()
+    if (votes.length > CHORD_VOTE_THRESHOLD) votes.shift()
 
-    const counts = {}
-    for (const v of votes) counts[v] = (counts[v] || 0) + 1
-    const [winner, winCount] = Object.entries(counts).sort((a, b) => b[1] - a[1])[0]
-
-    if (winCount >= CHORD_VOTE_THRESHOLD) {
+    // All last N detections must agree — one wrong reading resets the streak
+    if (votes.length >= CHORD_VOTE_THRESHOLD && votes.every(v => v === votes[0])) {
+      const winner = votes[0]
       setChordHistory(prev => {
         if (prev[prev.length - 1] === winner) return prev
         return [...prev.slice(-30), winner]

frontend/src/components/AudioCapture.jsx

@@ -44,7 +44,7 @@ function computeChroma(freqData, sampleRate, fftSize) {
 
   for (let bin = 2; bin < N; bin++) {
     const freq = bin * binHz
-    if (freq < 80 || freq > 6000) continue
+    if (freq < 80 || freq > 2000) continue
     const db = freqData[bin]
     if (db < NOISE_FLOOR) continue
 

frontend/src/lib/theory.js

@@ -187,6 +187,7 @@ export function matchChordFromChroma(chroma, keyInfo, bassPC = null, strictDiato
     CHORD_TYPES.sus4,
   ]
   let best = { name: null, score: -Infinity }
+  let secondScore = -Infinity
 
   for (let r = 0; r < 12; r++) {
     for (const type of matchTypes) {
@@ -210,15 +211,21 @@ export function matchChordFromChroma(chroma, keyInfo, bassPC = null, strictDiato
 
       const coverageScore = inEnergy / (inEnergy + outEnergy * 0.5)
       // Bass note matching chord root is a strong harmonic signal
-      const bassBonus     = (bassPC !== null && r === bassPC) ? 0.35 : 0
+      const bassBonus     = (bassPC !== null && r === bassPC) ? 0.15 : 0
       const diatonicBonus = diatonic.has(chordName) ? 0.15 : 0
 
       const finalScore = coverageScore + bassBonus + diatonicBonus
-      if (finalScore > best.score) best = { name: chordName, score: finalScore }
+      if (finalScore > best.score) {
+        secondScore = best.score
+        best = { name: chordName, score: finalScore }
+      } else if (finalScore > secondScore) {
+        secondScore = finalScore
+      }
     }
   }
 
-  return best.score > 0.42 ? best.name : null
+  // Require a clear winner — if two chords score too close it's a transition/ambiguity
+  return (best.score > 0.42 && best.score - secondScore > 0.08) ? best.name : null
 }
 
 // ─── Roman numeral notation ───────────────────────────────────────────────────