diff --git a/src/engine/audioEngine.js b/src/engine/audioEngine.js
index d962962..8e90623 100644
--- a/src/engine/audioEngine.js
+++ b/src/engine/audioEngine.js
@@ -35,8 +35,14 @@ export function unsubscribeTick(id) {
 
 function startMasterClock() {
   if (_masterClock) return;
-  _masterTime = Tone.now();
+  _masterTime = 0; // Will be set from first tick
+  let _started = false;
   _masterClock = new Tone.Clock((time) => {
+    // Capture start time from the FIRST callback — guarantees same clock source
+    if (!_started) {
+      _masterTime = time;
+      _started = true;
+    }
     const elapsed = time - _masterTime;
     for (const cb of _tickListeners.values()) {
       cb(time, elapsed);