ok question is...is there a huge difference in SPL between the 2 different types of inputs to an amp.quick recap on my issues.1 audioque 2.5 15" on a kicker kx600.1.somehow i seem to have lost my preamp outputs on my pioneer hu.not reading any volts at 50hz test signal.and my bass went from huge loud flexin bass to mudd at all freq.so i used the rear speaker wires off hu and the plug that came w/the amp for that type of connection and my bass sounds much better than with the faulty pre amps.but its not nearly as loud as it was before the pre amp went bad.i reset the gains but it didnt really help much,just made it louder at lower volumes.i am planning on a new hu with 4v outputs(pioneer 5900)my question is should this give me my loud bass back or could i have other issues.all grounds are good;big 3 in 4ga,solid ported box i built is sound,so it should be loud again with a new hu.i hope.