1st off what tuning frequency(HZ) will give you lots of spl and how do you know what freq. to tune your subs?Also how much of a difference in bass/spl will there be as far as 2-12's in a 4 cu.ft box vs a 4.5 cu ft box or 5 cu ft box?The subs recommended cu ft per sub is 1.30-3.20.Thanks