Wall building suggestions...

[da99jeep]

So Im thinking of rebuilding my box (again) Right now im running 6 DD1500 12's and i want to move hair.. ( i may got to 4 18's) its right now in a 12qbft top fire rear ported box (see my build link below to look) it kinda lifts the hair up, but i want full blown hair tricks.. and im thinking of walling it now. but i dont know if I should do just a flat wall, or try my hands on a bandpass.. and If i bandpass, what should I do. i dont know the first thing about building them. or even how to tune one. but i hear they move a hell of a lot more air than a standard flat wall. i was thinking of maybe doing one where its 2 ported boxes that the subs fire at each other, then they port into the rear of the box and through the center channel between the firing subs (im not sure what taht is.. 4th order? 6th order? nothings sealed though. but liek i said i dont know the first thing to do about tuning a box liek that.

rival904 has pretty much the design i want here. slightly tweaked for my Jeep.

http://www.stevemeadedesigns.com/board/topic/105559-rival904s-6-18s-walkthrough-build-box-is-done-and-in-page-7/page__st__20)

if anyone has any suggestions on what box i should build for a hair tricking ground pounder lemme know please.. any help is more than appreciated!