I have an xls 402 hooked up to a behringer board and sending to two peavey 15's. I've used it for a month and it has sounded great. All of sudden the lower frequencies of bass (like bass guitar or 808 sounds) have dropped down significantly. Because of this, the highs and mids are too much. I'm positive that it is the amp since i have hooked up a different amp and everything was ok. Any help as to what is going on and how i can fix it would be much appreciated.