2000 Suburban XL, dual alternators, Pioneer n-3, 2 JL Audio 1000/1 powering 4 kicker 12" L7 subs. I have a single box with 4 chambers. Internals are 1.6 cubes per sub and each sub has a 10" aero port facing the roof (subs are facing the tailgate) Long story short...I need it to hit lower! I know Its not the best set-up at all, but does anyone recommend any other box design? I do have a lot of space....yes I am new at this and right now I am lost. My friend has 2 l7's on the same amp in a sealed box and it almost matches my 4! Thanks guys