diff --git a/src/core/audio-interface/KGAudioInterface.test.ts b/src/core/audio-interface/KGAudioInterface.test.ts
index 798fae7..f002d31 100644
--- a/src/core/audio-interface/KGAudioInterface.test.ts
+++ b/src/core/audio-interface/KGAudioInterface.test.ts
@@ -24,6 +24,23 @@ import { ConfigManager } from '../config/ConfigManager';
 import { KGAudioInterface } from './KGAudioInterface';
 import { MIDI_PITCH_BEND_CENTER, midiPitchBendToNormalized } from '../../util/midiUtil';
 
+function createMockAudioBus() {
+  return {
+    resetLiveMidiPitchBend: vi.fn(),
+    setLiveMidiPitchBend: vi.fn(),
+    scheduleLiveMidiPitchBend: vi.fn(),
+    setLiveMidiExpression: vi.fn(),
+    scheduleLiveMidiExpression: vi.fn(),
+    setLiveMidiSustain: vi.fn(),
+    setAutomationVolume: vi.fn(),
+    setAutomationPan: vi.fn(),
+    scheduleAutomationPan: vi.fn(),
+    applyEffectiveVolume: vi.fn(),
+    getSolo: vi.fn().mockReturnValue(false),
+    shouldPlayWithSolo: vi.fn().mockReturnValue(true),
+  };
+}
+
 describe('KGAudioInterface preroll playback', () => {
   beforeEach(() => {
     vi.useFakeTimers();
@@ -125,14 +142,7 @@ describe('KGAudioInterface preroll playback', () => {
     const track = createMockMidiTrack({ id: 1, regions: [region] });
     const project = createMockProject({ tracks: [track] });
     const audio = KGAudioInterface.instance();
-    const audioBus = {
-      resetLiveMidiPitchBend: vi.fn(),
-      setLiveMidiPitchBend: vi.fn(),
-      scheduleLiveMidiPitchBend: vi.fn(),
-      setLiveMidiExpression: vi.fn(),
-      setLiveMidiSustain: vi.fn(),
-      shouldPlayWithSolo: vi.fn().mockReturnValue(true),
-    };
+    const audioBus = createMockAudioBus();
 
     ;(audio as unknown as { trackAudioBuses: Map<string, unknown> }).trackAudioBuses.set('1', audioBus);
     audio.preparePlayback(project, 0);
@@ -152,14 +162,7 @@ describe('KGAudioInterface preroll playback', () => {
     const track = createMockMidiTrack({ id: 1, regions: [region] });
     const project = createMockProject({ tracks: [track] });
     const audio = KGAudioInterface.instance();
-    const audioBus = {
-      resetLiveMidiPitchBend: vi.fn(),
-      setLiveMidiPitchBend: vi.fn(),
-      scheduleLiveMidiPitchBend: vi.fn(),
-      setLiveMidiExpression: vi.fn(),
-      setLiveMidiSustain: vi.fn(),
-      shouldPlayWithSolo: vi.fn().mockReturnValue(true),
-    };
+    const audioBus = createMockAudioBus();
 
     ;(audio as unknown as { trackAudioBuses: Map<string, unknown> }).trackAudioBuses.set('1', audioBus);
     audio.preparePlayback(project, 0);
@@ -178,14 +181,7 @@ describe('KGAudioInterface preroll playback', () => {
     const track = createMockMidiTrack({ id: 1, regions: [region] });
     const project = createMockProject({ tracks: [track] });
     const audio = KGAudioInterface.instance();
-    const audioBus = {
-      resetLiveMidiPitchBend: vi.fn(),
-      setLiveMidiPitchBend: vi.fn(),
-      scheduleLiveMidiPitchBend: vi.fn(),
-      setLiveMidiExpression: vi.fn(),
-      setLiveMidiSustain: vi.fn(),
-      shouldPlayWithSolo: vi.fn().mockReturnValue(true),
-    };
+    const audioBus = createMockAudioBus();
 
     ;(audio as unknown as { trackAudioBuses: Map<string, unknown> }).trackAudioBuses.set('1', audioBus);
     audio.preparePlayback(project, 2);
@@ -206,14 +202,7 @@ describe('KGAudioInterface preroll playback', () => {
     project.setLoopingRange([1, 1]);
 
     const audio = KGAudioInterface.instance();
-    const audioBus = {
-      resetLiveMidiPitchBend: vi.fn(),
-      setLiveMidiPitchBend: vi.fn(),
-      scheduleLiveMidiPitchBend: vi.fn(),
-      setLiveMidiExpression: vi.fn(),
-      setLiveMidiSustain: vi.fn(),
-      shouldPlayWithSolo: vi.fn().mockReturnValue(true),
-    };
+    const audioBus = createMockAudioBus();
 
     ;(audio as unknown as { trackAudioBuses: Map<string, unknown> }).trackAudioBuses.set('1', audioBus);
     audio.preparePlayback(project, 5);
diff --git a/src/test/mocks/tone.ts b/src/test/mocks/tone.ts
index e29846a..0733dfa 100644
--- a/src/test/mocks/tone.ts
+++ b/src/test/mocks/tone.ts
@@ -102,6 +102,18 @@ export const MockGain = vi.fn().mockImplementation((initialValue: number = 1) =>
   dispose: vi.fn()
 }));
 
+// Mock Panner node
+export const MockPanner = vi.fn().mockImplementation((initialValue: number = 0) => ({
+  pan: {
+    value: initialValue,
+    setValueAtTime: vi.fn(),
+  },
+  connect: vi.fn(),
+  disconnect: vi.fn(),
+  dispose: vi.fn(),
+  toDestination: vi.fn(),
+}));
+
 // Mock Meter
 export const MockMeter = vi.fn().mockImplementation(() => ({
   getValue: vi.fn().mockReturnValue(-Infinity),
@@ -120,6 +132,7 @@ export const ToneMock = {
   Destination: MockDestination,
   ToneAudioBuffer: MockToneAudioBuffer,
   Gain: MockGain,
+  Panner: MockPanner,
   Meter: MockMeter,
   
   // Context management