OK this is what I have, 1-12" single 4ohm PG Xmax sub PWR 400 wavelength amp-600wrms @ 4ohms and clarion x-over pioneer deck box is 2.5cuft tuned to 30hz, with-in specs of what PG suggests. gains are set correct. This is what happens, I play a song like, Late night tip or some lil john, songs that I think hit pretty low, and SHIP does it get loud and low, but as soon as I put on anything that has hard bass, it doesn't get near as loud I mean nothing, nothing short of cranking it and adding bass boost will help, but this isn't what I want to have to do. This is in a 90 acura TRUNK not hatchback, sub facing back of trunk and the port is on the same side as the sub. my thoughts. box is tuned to low maybe tune to, 33-35hz sub is just not a SQ sub, very possible I've also tried higher x-over points like 60-80, this is a little better Volume is usually 30 of 40 when I crank it. thanks for any help