I have a set of Polk Audio MM521 speakers mounted in my motorcycle saddlebags that I am powering with a Rockford Fosgate PBR300X2 Punch amp. Anything above 24 on the volume the speakers start to pop and the sound is gone. I have tried every adjustment possible on the amp and nothing solves the problem. I'm guessing that the problem may be something to do with the crossover on the speakers. The amp has a built in crossover. Is there a way to by pass the crossover on the speakers?