I have some M-audio BX5a monitors. I like them. but I need a subwoofer mannnnn. the one that maudio sells is $400. I don't know about alll that. Any suggestions on a cheaper one? should I not get a cheaper one? Is $400 not a bad price compared to the monitors I have? I know the ones I have aren't at all the best quality. The size is perfect for my little studio. I just want some more bass. Help! thank you. boom.