diff --git a/libs/core/music.ts b/libs/core/music.ts
index 38023fb4cd5..1d910e44bc4 100644
--- a/libs/core/music.ts
+++ b/libs/core/music.ts
@@ -670,7 +670,7 @@ namespace music {
                 current = notes.charAt(note);
                 if (current === "#") current = notes.charAt(note - 1) + current
 
-                octave = Math.idiv((melody[i] - 23), 12)
+                octave = Math.idiv((melody[i] - 24), 12)
             }
 
             const duration = melody[i + 1];