i have 3 12" Dual 4 Ohm Rockford Fosgate Punch Series Subwoofer P3'S and a Punch T1500-1bdCP , i want it louder can anyone sugest if adding another 12'' with the same amp soud louder or not, and if you know about the speakers i have can it be wired at 1ohm for all four ? they are set up currently at 2.67ohms