hi all, i got a question, i decided to go with a poweramp, bass preamp instead of a pre-made bass head. i havent got my bass preamp yet but i got my poweramp (575 watts per channel@4 ohms and bridged-1570 watts at 4ohms.) and plugged it to my 15" cab. the 15 is a carvin 600watt driver at 4ohms. and i have my bass is an active ibanez soundgear. i didnt know what to expect but i expected to be loud with no eq of course, but its not loud. i tried both, on one side stereo and on bridged and i got just about the same low volume. am i just missing the preamp or do i simply need another cab of speakers??help...