I am wondering if I can do this? I have a RockFord BD500 sub amp. Running 2 12" Dayton Loudspeaker DSQ 12.4 in parallel. 2 ohm. Was told that I could run a third in parallel as long as I used them all in a Sealed box. Currently using two in a seled box. Obcon is supposed to make a box that should fit in the back of my Escape.