How big is your box what is the tuning on the box and where do you have your subsonic set the box should be around 2 cubic ft tuned to 32 to 35 for daily and your subsonic should be set to 35 onlt time I've seen this happen is when I burp 20k or more it will happen after about 50 or 60 burps lol and for daily I have seen it happen to when the guy was running a 15 in 5 cubes tuned to 40 with the subsonic set to 20 playing chopped and screwed lol if everything is set right then I have no clue then.