delay isn't the problem here

keyboard/preonic/keymaps/default/keymap.c

@@ -315,7 +315,7 @@ void matrix_init_user(void) {
 
 void play_startup_tone()
 {
-  PLAY_NOTE_ARRAY(music_scale, false, 0);
+  PLAY_NOTE_ARRAY(start_up, false, 0);
 }
 
 void play_goodbye_tone()

quantum/audio.c

@@ -213,7 +213,6 @@ void audio_init() {
     #endif
 
     inited = true;
-    _delay_ms(500);
 }
 
 void stop_all_notes() {