Ok In my cavalier I took out the back seat and built a box that is 3cu. ft. per sub with a 2"x12" vent that is 14" long. In the box I have 2 15" Xtant a1544's. (not the a1544a) and for an amp I have a Ultra Liniar UL400HC. I have the subs wired up to 1 ohm (at one ohm the amp puts out 1200 watts rms, subs are only supposed to take 500 watts rms) I have the gain on the amp turned just a little more than half way up. The bass is just so so. But it's not as loud as I would like it to be. So I want louder. I don't want to spend another grand on the system so what could I do? Thinking of maybe getting 2 15" solo-baric L5's. But I Don't know. Is this amp an ok amp?