Thats what I have right now, a 40x36x14 with one bl. i can rebuild to use max space 40x40x15. Ive blown both 18s and rebuild one and have one just sitting in the corner asking to be rebuilt. Id like to do the 2 18s in the that 40x40x15 box ported , but that would be about 3.66^2 ft. Right now with one im at 6.5x with one. Will the two in the slightly smaller per sub box be more out put then the larger per sub box with just one?