diff --git a/app/static/js/services/soundfontPlayer.js b/app/static/js/services/soundfontPlayer.js
index 0ee05eb..b44d2ad 100644
--- a/app/static/js/services/soundfontPlayer.js
+++ b/app/static/js/services/soundfontPlayer.js
@@ -163,8 +163,14 @@
 
         stopNote: function (channel, pitch) {
             if (channel < 0 || channel > 15) return;
+            console.log("[SonicSF] stopNote ch=" + channel + " pitch=" + pitch + " init=" + _initialized);
             if (_initialized && _synthInstance) {
-                try { _synthInstance.noteOff(channel, pitch); } catch (e) {}
+                try { _synthInstance.noteOff(channel, pitch); } catch (e) {
+                    console.warn("[SonicSF] noteOff threw:", e);
+                }
+            } else {
+                // Oscillator fallback: stop is handled by the 60000ms timeout
+                // Nothing to do — oscillator auto-stops after durationMs
             }
         },