i heard that bandpass boxes only play a narrow band of frequencies. does anyone know aproximately what frequency range it plays? i know it differs for every box, but what is the usual. im assuming i would need a subsonic filter, and the low pass filter already on the amp. if i listen to rap, and ONLY rap, would this be the best box for me? my subs are only getting about half of there max rms power. should i stay with the sealed, or should i get a bandpass? space is not a factor.