refactor audio playback by normalizing velocity for improved sound consistency

index.html

@@ -541,7 +541,7 @@
                             Tone.Frequency(n.note, "midi").toNote(),
                             Math.min(n.duration, 1.5), // limit duration
                             Tone.now() + Math.random() * 0.02,
-                            velocity
+                            normalizedVelocity
                         );
                 });
             }