diff --git a/app/static/js/services/soundfontPlayer.js b/app/static/js/services/soundfontPlayer.js
index 20ec72e..639a5e0 100644
--- a/app/static/js/services/soundfontPlayer.js
+++ b/app/static/js/services/soundfontPlayer.js
@@ -13,6 +13,7 @@
     let _channels = Array.from({ length: 16 }, () => ({ bank: 0, program: 0, isPercussion: false }));
     let _nextMelodicChannel = 0;
     let _sustainStates = new Array(16).fill(false);
+    let _engineChMap = {};
     let _leftBufPtr = null;
     let _rightBufPtr = null;
     let _renderTimer = null;
@@ -229,6 +230,14 @@
                 var ok = await this.loadSoundFont(sfId);
                 if (!ok) return;
             }
+            var engKey = (sfId || '') + ':' + bank + ':' + program;
+            if (!_engineChMap[engKey]) {
+                var allocCh = this.allocateChannel(bank);
+                _engineChMap[engKey] = allocCh;
+                channel = allocCh;
+            } else {
+                channel = _engineChMap[engKey];
+            }
             try {
                 _fluidModule._fluid_synth_bank_select(_synthPtr, channel, bank);
             } catch (e) {}
@@ -278,9 +287,14 @@
                 bank = bank !== undefined ? bank : (synthEngine.soundfont_bank || 0);
                 program = program !== undefined ? program : (synthEngine.soundfont_program || 0);
             }
-            var channel = this.allocateChannel(bank);
-            this.selectInstrument(channel, bank, program, synthEngine && synthEngine.soundfont_id);
-            return channel;
+            var sfId = synthEngine && synthEngine.soundfont_id;
+            var engKey = (sfId || '') + ':' + bank + ':' + program;
+            if (!_engineChMap[engKey]) {
+                var channel = this.allocateChannel(bank);
+                _engineChMap[engKey] = channel;
+            }
+            this.selectInstrument(_engineChMap[engKey], bank, program, sfId);
+            return _engineChMap[engKey];
         },
 
         getChannelState: function (channel) {
@@ -342,11 +356,16 @@
             var ch = channel;
             var usedBank = 0, usedProg = 0;
             if (synthEngine) {
-                if (ch === undefined) {
-                    ch = synthEngine.soundfont_bank === 128 ? 9 : 0;
-                }
                 usedBank = synthEngine.soundfont_bank || 0;
                 usedProg = synthEngine.soundfont_program || 0;
+                var engKey = (synthEngine.soundfont_id || '') + ':' + usedBank + ':' + usedProg;
+                var mappedCh = _engineChMap[engKey];
+                if (mappedCh !== undefined) {
+                    ch = mappedCh;
+                } else if (ch === undefined) {
+                    ch = usedBank === 128 ? 9 : 0;
+                }
+                if (ch === undefined) ch = (usedBank === 128 ? 9 : 0);
                 try {
                     _fluidModule._fluid_synth_bank_select(_synthPtr, ch, usedBank);
                 } catch (e) {}
@@ -356,8 +375,9 @@
                 if (channel === undefined) channel = ch;
             } else if (program !== undefined) {
                 usedProg = program;
+                if (ch === undefined) ch = 0;
                 try {
-                    _fluidModule._fluid_synth_program_change(_synthPtr, ch || 0, usedProg);
+                    _fluidModule._fluid_synth_program_change(_synthPtr, ch, usedProg);
                 } catch (e) {}
             }
             if (ch === undefined) ch = (usedBank === 128 ? 9 : 0);