diff --git a/src/engine/platform/sound/nes/apu.c b/src/engine/platform/sound/nes/apu.c
index a278cbf74..70eddc8e7 100644
--- a/src/engine/platform/sound/nes/apu.c
+++ b/src/engine/platform/sound/nes/apu.c
@@ -226,4 +226,6 @@ void apu_turn_on(struct NESAPU* a, BYTE apu_type) {
 	a->DMC.length = 1;
 	a->DMC.address_start = 0xC000;
   a->apu.odd_cycle = 0;
+  // come non viene inizializzato? Vorrei qualche spiegazione...
+  a->r4011.frames = 0;
 }