diff --git a/app/static/js/app.jsx b/app/static/js/app.jsx
index c5d61d4..221fdfd 100644
--- a/app/static/js/app.jsx
+++ b/app/static/js/app.jsx
@@ -1767,7 +1767,7 @@ async function fxRtStart() {
   fxRt.sessionId = st.session_id;
   fxRtGuiPushShm();
   try {
-    await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241800`);
+    await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241900`);
     if (token !== fxRt.startToken) { fxRt.starting = false; return; }
     fxRt.node = new AudioWorkletNode(ctx, 'sf-fx-realtime', { numberOfInputs: 1, numberOfOutputs: 1, outputChannelCount: [2] });
     const u = new URL(API_BASE_URL);
@@ -23839,7 +23839,7 @@ const App = () => {
     fxRtTracks[key] = entry;
     fxRtGuiPushShm();
     try {
-      await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241800`);
+      await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241900`);
       const node = new AudioWorkletNode(ctx, 'sf-fx-realtime', { numberOfInputs: 1, numberOfOutputs: 1, outputChannelCount: [2] });
       entry.node = node;
       const u = new URL(API_BASE_URL);
diff --git a/app/static/js/app.precompiled.js b/app/static/js/app.precompiled.js
index ace5c01..b8437a1 100644
--- a/app/static/js/app.precompiled.js
+++ b/app/static/js/app.precompiled.js
@@ -304,7 +304,7 @@ else if(fxRt.chainKey!==ck){fxRtSetChain(chain);fxRt.chainKey=ck;return;}else re
 // node → bypass vô hiệu. Mỗi fxRtStop() bump startToken → mọi checkpoint
 // dưới đây thấy mismatch → hủy session vừa tạo, không nối node.
 const token=++fxRt.startToken;fxRt.starting=true;const ctx=getAudioContext();if(!ctx||!ctx.audioWorklet||!masterBus||!masterBus.output||!masterBus.analyser||!masterBus.masterFxGain||!masterBus.masterFxDryGain)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:false}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:false});let st;try{st=await window.SonicAPI.fxRealtimeStart({fx_chain:chainPayload,sample_rate:ctx.sampleRate||44100});}catch(e){console.warn('[FX RT] start fail:',e);showToast('Không khởi động VST FX realtime: '+(e.message||e),'warning');fxRt.starting=false;return;}if(token!==fxRt.startToken){// Bypass/stop giữa lúc engine đang load chain — hủy session vừa tạo.
-console.warn('[FX RT] start cancelled mid-flight — session stopped');try{window.SonicAPI.fxRealtimeStop({session_id:st.session_id}).catch(()=>{});}catch(e2){}fxRt.starting=false;return;}fxRt.sessionId=st.session_id;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241800`);if(token!==fxRt.startToken){fxRt.starting=false;return;}fxRt.node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';const tok=localStorage.getItem('sonic_token')||'';const wsUrl=`${wsProto}${u.host}${st.ws_url}${tok?'?token='+encodeURIComponent(tok):''}`;const ws=new WebSocket(wsUrl);fxRt.ws=ws;ws.binaryType='arraybuffer';ws.onopen=()=>{if(token!==fxRt.startToken){try{ws.close();}catch(e){}fxRt.starting=false;return;}fxRt.active=true;fxRt.starting=false;fxRt.inQueue=[];// bỏ audio stale sản xuất trước khi WS open (~4s load VST) — hết lag khởi đầu
+console.warn('[FX RT] start cancelled mid-flight — session stopped');try{window.SonicAPI.fxRealtimeStop({session_id:st.session_id}).catch(()=>{});}catch(e2){}fxRt.starting=false;return;}fxRt.sessionId=st.session_id;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241900`);if(token!==fxRt.startToken){fxRt.starting=false;return;}fxRt.node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';const tok=localStorage.getItem('sonic_token')||'';const wsUrl=`${wsProto}${u.host}${st.ws_url}${tok?'?token='+encodeURIComponent(tok):''}`;const ws=new WebSocket(wsUrl);fxRt.ws=ws;ws.binaryType='arraybuffer';ws.onopen=()=>{if(token!==fxRt.startToken){try{ws.close();}catch(e){}fxRt.starting=false;return;}fxRt.active=true;fxRt.starting=false;fxRt.inQueue=[];// bỏ audio stale sản xuất trước khi WS open (~4s load VST) — hết lag khởi đầu
 try{fxRtPushAllParams();}catch(e){}};ws.onmessage=ev=>{// Gap 8 (PDC realtime): text frame {cmd:'latency', total} tu server ->
 // cap nhat delay dry-bypass path (bu latency chain VST3 realtime).
 if(typeof ev.data==='string'){try{const d=JSON.parse(ev.data);if(d&&d.cmd==='latency'&&typeof d.total==='number'){fxRt.latencyTotal=d.total;// Chi delay dry path khi crossfade da xong (dry silent) — ap som
@@ -1699,7 +1699,7 @@ fxRtTrackReconcile(trackId,node,track);}catch(e){console.warn('rebuildTrackFxGra
 // Cần activeTrackNodesRef/isPlayingRef. Session giống master (fxRtStart):
 // fetch start → AudioWorkletNode 'sf-fx-realtime' → WS; WS open → splice
 // worklet vào chain hiện tại (đọc mods MỚI NHẤT — an toàn với rebuild).
-const fxRtTrackStart=async(trackId,track,path)=>{const key=trackId+':'+path;const chain=fxRtTrackChain(track);if(!chain.length)return;if(fxRtTracks[key]){if(!fxRtTracks[key].node||fxRtTracks[key].node.context!==getAudioContext())fxRtTrackStop(trackId,path,true);else return;}const ctx=getAudioContext();if(!ctx||!ctx.audioWorklet)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:false}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:false});let st;try{st=await window.SonicAPI.fxRealtimeStart({fx_chain:chainPayload,sample_rate:ctx.sampleRate||44100});}catch(e){console.warn('[FX RT track] start fail',trackId,path,e);return;}const entry={sessionId:st.session_id,ws:null,node:null,ready:false,path,spliced:null,chainKey:fxRtTrackChainKey(chain),paramsBySlot:chain.map(s=>fxRtEntryParams(s,null)),inQueue:[],pumpTimer:null,lastInSent:0};fxRtTracks[key]=entry;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241800`);const node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});entry.node=node;const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';const tok=localStorage.getItem('sonic_token')||'';const ws=new WebSocket(`${wsProto}${u.host}${st.ws_url}${tok?'?token='+encodeURIComponent(tok):''}`);entry.ws=ws;ws.binaryType='arraybuffer';ws.onopen=()=>{entry.ready=true;entry.inQueue=[];// bỏ audio stale trước khi WS open — hết lag khởi đầu
+const fxRtTrackStart=async(trackId,track,path)=>{const key=trackId+':'+path;const chain=fxRtTrackChain(track);if(!chain.length)return;if(fxRtTracks[key]){if(!fxRtTracks[key].node||fxRtTracks[key].node.context!==getAudioContext())fxRtTrackStop(trackId,path,true);else return;}const ctx=getAudioContext();if(!ctx||!ctx.audioWorklet)return;const chainPayload=chain.map(s=>s.type==='vst3'?{type:'vst3',path:s.path,name:s.name||s.path,preset_b64:s.preset_b64||'',bypass:false}:{type:'builtin',id:s.type,params:s.params&&Object.keys(s.params).length?s.params:{},bypass:false});let st;try{st=await window.SonicAPI.fxRealtimeStart({fx_chain:chainPayload,sample_rate:ctx.sampleRate||44100});}catch(e){console.warn('[FX RT track] start fail',trackId,path,e);return;}const entry={sessionId:st.session_id,ws:null,node:null,ready:false,path,spliced:null,chainKey:fxRtTrackChainKey(chain),paramsBySlot:chain.map(s=>fxRtEntryParams(s,null)),inQueue:[],pumpTimer:null,lastInSent:0};fxRtTracks[key]=entry;fxRtGuiPushShm();try{await ctx.audioWorklet.addModule(`${API_BASE_URL}/static/js/sf-fx-realtime.js?v=202608241900`);const node=new AudioWorkletNode(ctx,'sf-fx-realtime',{numberOfInputs:1,numberOfOutputs:1,outputChannelCount:[2]});entry.node=node;const u=new URL(API_BASE_URL);const wsProto=u.protocol==='https:'?'wss://':'ws://';const tok=localStorage.getItem('sonic_token')||'';const ws=new WebSocket(`${wsProto}${u.host}${st.ws_url}${tok?'?token='+encodeURIComponent(tok):''}`);entry.ws=ws;ws.binaryType='arraybuffer';ws.onopen=()=>{entry.ready=true;entry.inQueue=[];// bỏ audio stale trước khi WS open — hết lag khởi đầu
 fxRtTrackSplice(trackId,path);try{(entry.paramsBySlot||[]).forEach((pl,slot)=>pl.forEach(p=>ws.send(JSON.stringify({cmd:'set_param',slot,key:p.key,value:p.value}))));}catch(e){}};ws.onmessage=ev=>{if(!(ev.data instanceof ArrayBuffer)||!entry.node)return;const f=new Float32Array(ev.data);const half=f.length/2;const l=new Float32Array(half);const r=new Float32Array(half);for(let i=0;i<half;i++){l[i]=f[i*2];r[i]=f[i*2+1];}entry.node.port.postMessage({type:'out',l,r});};ws.onclose=()=>fxRtTrackStop(trackId,path,true);ws.onerror=()=>{try{ws.close();}catch(e){}};entry.node.port.onmessage=ev=>{const d=ev.data;if(!d||!entry.ws)return;if(d.type==='set_param'){try{entry.ws.send(JSON.stringify({cmd:'set_param',slot:d.slot,key:d.key,value:d.value}));}catch(e){}return;}if(d.type!=='in')return;// Burst 4 block (1024 mẫu) → tách 4 WS frame 512 floats → bridge batch 4.
 // Pace 1 burst/21ms (giống master) — tránh dồn frame sau stall làm tràn ring.
 entry.inQueue.push(d);const pump=()=>{if(!entry.inQueue.length)return;const now=Date.now();while(entry.inQueue.length&&now-entry.lastInSent>=FXRT_BURST_MS){entry.lastInSent=now;const dd=entry.inQueue.shift();if(entry.ws&&entry.ws.readyState===1){try{const f=new Float32Array(dd.data);if(f.length>512){for(let i=0;i<f.length;i+=512)entry.ws.send(f.slice(i,i+512).buffer);}else{entry.ws.send(dd.data);}}catch(e){}}}if(entry.inQueue.length){if(entry.pumpTimer)clearTimeout(entry.pumpTimer);entry.pumpTimer=setTimeout(pump,Math.max(1,FXRT_BURST_MS-(now-entry.lastInSent)));}else if(entry.pumpTimer){clearTimeout(entry.pumpTimer);entry.pumpTimer=null;}};pump();};}catch(e){console.warn('[FX RT track] setup fail',trackId,path,e);fxRtTrackStop(trackId,path,true);}};const fxRtTrackUnsplice=(trackId,path)=>{const entry=fxRtTracks[trackId+':'+path];if(!entry||!entry.spliced||!entry.node)return;try{entry.node.disconnect();try{entry.spliced.tail.connect(entry.spliced.dest);}catch(e){}entry.spliced=null;}catch(e){console.warn('[FX RT track] unsplice fail',trackId,path,e);}};// Chain đổi trên session ĐANG CHẠY — set_chain KHÔNG restart (bridge swap
diff --git a/app/static/js/sf-fx-realtime.js b/app/static/js/sf-fx-realtime.js
index 38864d2..97b3fc0 100644
--- a/app/static/js/sf-fx-realtime.js
+++ b/app/static/js/sf-fx-realtime.js
@@ -38,6 +38,7 @@ class SfFxRealtimeProcessor extends AudioWorkletProcessor {
     this.holdPos = 0;
     this.holdLeft = 0;
     this.holdFadeLeft = 0;     // mẫu còn lại của fade-out sau HOLD
+    this.silenced = false;     // đã fade về 0 → im lặng; resume phải fade-in, không hold lại
     this.bufLen = this.BLOCK * this.BURST;
     this.inL = new Float32Array(this.bufLen);
     this.inR = new Float32Array(this.bufLen);
@@ -111,9 +112,11 @@ class SfFxRealtimeProcessor extends AudioWorkletProcessor {
         }
         // Underrun giữa stream — chuyển hold (không cắt zero ngay → hết click).
         this.playing = false;
-        this.holdPos = 0;
-        this.holdLeft = this.HOLD * this.BLOCK;
-        this.holdFadeLeft = this.HOLD_FADE * this.BLOCK;
+        if (!this.silenced) {  // đã im lặng (fade xong) → giữ im lặng, không hold lại block cũ
+          this.holdPos = 0;
+          this.holdLeft = this.HOLD * this.BLOCK;
+          this.holdFadeLeft = this.HOLD_FADE * this.BLOCK;
+        }
       }
       // Không phát: resume khi đủ block (lần đầu chờ FILL; sau đó chỉ cần 1
       // block — hold che khoảng chờ).
@@ -123,11 +126,13 @@ class SfFxRealtimeProcessor extends AudioWorkletProcessor {
         const wasFading = this.holdFadeLeft > 0 && this.holdLeft <= 0;
         this.holdLeft = 0;
         this.holdFadeLeft = 0;
-        if (wasFading && this.hasStarted) {
-          // Resume giữa fade-out: gain đang <1 → fade-in nhanh tránh jump ~0→1
+        if ((wasFading || this.silenced) && this.hasStarted) {
+          // Resume giữa fade-out / sau im lặng: gain đang <1 (hoặc 0) →
+          // fade-in nhanh tránh jump ~0→1 (click sau long stall).
           this.outGain = 0;
           this.fadeLeft = this.FADE;
         }
+        this.silenced = false;
         if (!this.hasStarted) {
           this.hasStarted = true;
           this.outGain = 0;
@@ -154,6 +159,7 @@ class SfFxRealtimeProcessor extends AudioWorkletProcessor {
         this.holdPos++;
         if (this.holdPos >= this.BLOCK) this.holdPos = 0;
         this.holdFadeLeft--;
+        if (this.holdFadeLeft <= 0) this.silenced = true;  // fade xong → im lặng thật
         continue;
       }
       outL[i] = 0;
diff --git a/app/templates/index.html b/app/templates/index.html
index 576f44e..0b3bf9e 100644
--- a/app/templates/index.html
+++ b/app/templates/index.html
@@ -51,7 +51,7 @@
     <script src="/static/js/services/promptTemplateManager.js?v=202607281039"></script>
     <script src="/static/js/services/undoRedoEngine.js?v=202607290941"></script>
     <script src="/static/js/services/chordTheory.js?v=202608211300"></script>
-    <script src="/static/js/app.precompiled.js?v=202608241142" defer></script>
+    <script src="/static/js/app.precompiled.js?v=202608241203" defer></script>
     <link rel="stylesheet" href="/static/css/styles.css?v=202607271016">
     <style>
         :root {