FIX: Piano roll track 4 phát âm thanh instrument track 3

app/static/js/app.jsx

@@ -7722,14 +7722,16 @@ const PianoRollTabEditor = ({ st, zoom, bpm, viewportWidth, activeTracks, onClos
         try { previewNodesRef.current.gain.disconnect(); } catch(e) {}
         previewNodesRef.current = null;
       }
-      if (window.SonicSF && window.SonicSF._playNoteFallback) {
+      if (window.SonicSF && window.SonicSF.playNote) {
         const ctx = getAudioContext();
         var dwTrk = activeTracks.find(function(t) { return t.id === st.trackId; });
         var dwCh = dwTrk ? assignTrackMidiChannel(dwTrk, activeTracks) : 0;
         var dwPitch = snapToScaleRef.current ? snapPitchToScale(pitch, selectedScaleRef.current) : pitch;
         var dwDurMs = Math.max(100, Math.round(initialDur * (60 / bpm) * 1000));
-        var dwNodes = window.SonicSF._playNoteFallback(dwPitch, Math.round(brushVelocityRef.current * 127), dwDurMs, ctx.currentTime, dwTrk ? dwTrk.instrumentProgram : undefined, null, dwCh, dwTrk ? dwTrk.synth_engine : undefined);
-        if (dwNodes) previewNodesRef.current = dwNodes;
+        // playNote (FluidSynth — nhạc cụ THẬT của track). _playNoteFallback chỉ
+        // là oscillator beep (sai âm với percussion/soundfont — user: note vẽ
+        // mới nghe nhạc cụ track trước).
+        window.SonicSF.playNote(dwPitch, Math.round(brushVelocityRef.current * 127), dwDurMs, ctx.currentTime, dwTrk ? dwTrk.instrumentProgram : undefined, null, dwCh, dwTrk ? dwTrk.synth_engine : undefined);
       }
     }
   };
@@ -7818,13 +7820,14 @@ const PianoRollTabEditor = ({ st, zoom, bpm, viewportWidth, activeTracks, onClos
 
       function playDrawPreview(p, durMs) {
         stopPreviewNote();
-        if (window.SonicSF && window.SonicSF._playNoteFallback) {
+        if (window.SonicSF && window.SonicSF.playNote) {
           var pvCtx = getAudioContext();
           var pvTrk = activeTracks.find(function(t) { return t.id === st.trackId; });
           var pvCtxInst = resolveTrackInstrumentCtx(pvTrk, activeTracks);
           var pvVel = Math.round(brushVelocityRef.current * 127);
-          var pvNodes = window.SonicSF._playNoteFallback(p, pvVel, durMs, pvCtx.currentTime, pvCtxInst.program, null, pvCtxInst.ch, pvCtxInst.synthEngine);
-          if (pvNodes) previewNodesRef.current = pvNodes;
+          // playNote (FluidSynth — nhạc cụ THẬT). _playNoteFallback = oscillator
+          // beep sai âm (percussion/soundfont).
+          window.SonicSF.playNote(p, pvVel, durMs, pvCtx.currentTime, pvCtxInst.program, null, pvCtxInst.ch, pvCtxInst.synthEngine);
           previewPitchRef.current = p;
         }
       }

app/static/js/services/soundfontPlayer.js

@@ -153,7 +153,7 @@
                             // expected notice when a soundfont simply has no
                             // preset for a bank (e.g. bank 128 on a melodic-only
                             // font) — the note is just silent, not an error.
-                            if (msg && msg.indexOf('No preset found on channel') !== -1) return;
+                            if (msg && (msg.indexOf('No preset found on channel') !== -1 || msg.indexOf('There is no preset with bank number') !== -1)) return;
                             console.warn('[FluidSynth:err]', msg);
                         }
                     });
@@ -562,7 +562,22 @@
                         console.log('[SonicSF] selectProgram for channel:', ch, 'sfHandle:', sfHandle, 'bank:', finalBank, 'prog:', finalProg);
                         if (sfHandle !== undefined) {
                             try {
-                                _fluidModule._fluid_synth_program_select(_synthPtr, ch, sfHandle, finalBank, finalProg);
+                                var _selRet = _fluidModule._fluid_synth_program_select(_synthPtr, ch, sfHandle, finalBank, finalProg);
+                                // Percussion (bank 128) preset không tồn tại trong
+                                // font → fallback preset trống hợp lệ (GM kit 48 →
+                                // preset đầu font) — nếu không, noteon trên preset
+                                // rỗng = CÂM (track percussion "1 âm đầu rồi câm").
+                                if (_selRet !== 0 && finalBank === 128) {
+                                    var _cands = [[128, 48], [0, 0], [128, 1], [0, 48]];
+                                    for (var _ci = 0; _ci < _cands.length; _ci++) {
+                                        try {
+                                            if (_fluidModule._fluid_synth_program_select(_synthPtr, ch, sfHandle, _cands[_ci][0], _cands[_ci][1]) === 0) {
+                                                finalBank = _cands[_ci][0]; finalProg = _cands[_ci][1];
+                                                break;
+                                            }
+                                        } catch (e) {}
+                                    }
+                                }
                             } catch (e) {}
                         } else {
                             try { _fluidModule._fluid_synth_bank_select(_synthPtr, ch, finalBank); } catch (e) {}
@@ -645,7 +660,11 @@
             var oscType = 'triangle';
             var attackTime = 0.03, decayTime = 0.1, sustainLevel = 0.5, releaseTime = 0.2, volFactor = 0.25;
             var prog = program !== undefined ? parseInt(program) : 0;
-            if (channel !== undefined && channel >= 0 && channel < 16) {
+            // CHỈ dùng cache channel khi KHÔNG có program/synthEngine được
+            // truyền — trước đây override program của track bằng cache channel
+            // (bị track khác cùng channel ghi đè → preview note vẽ mới mang
+            // nhạc cụ của track TRƯỚC).
+            if (program === undefined && channel !== undefined && channel >= 0 && channel < 16) {
                 prog = _channels[channel].program || prog;
             }
             if (prog >= 0 && prog <= 7) { oscType = 'sine'; decayTime = 0.3; sustainLevel = 0.1; releaseTime = 0.2; }

app/templates/index.html

@@ -16,7 +16,7 @@
     <script src="/static/js/services/audioEngine.js?v=202607271016"></script>
     <script src="/static/js/services/storage.js?v=202608038200"></script>
     <script src="/static/js/services/soundfontStorage.js?v=202607271016"></script>
-    <script src="/static/js/services/soundfontPlayer.js?v=202608052355"></script>
+    <script src="/static/js/services/soundfontPlayer.js?v=202608060130"></script>
     <script src="/static/js/services/aiGateway.js?v=202608037200"></script>
     <script src="/static/js/services/dawCommandDispatcher.js?v=202607271016"></script>
     <script src="/static/js/services/pianoRollTabService.js?v=202607272044"></script>
@@ -24,7 +24,7 @@
     <script src="/static/js/services/midiExtractor.js?v=202607281052"></script>
     <script src="/static/js/services/promptTemplateManager.js?v=202607281039"></script>
     <script src="/static/js/services/undoRedoEngine.js?v=202607290941"></script>
-    <script src="/static/js/app.precompiled.js?v=202608060030" defer></script>
+    <script src="/static/js/app.precompiled.js?v=202608060130" defer></script>
     <link rel="stylesheet" href="/static/css/styles.css?v=202607271016">
     <style>
         :root {