Building a 4th order for a friend for 2 sa 12's. 2:1 ratio, 1 cubic foot sealed per sub, & 2 per sub ported. Will two 6in aeroports be enough port area to avoid port noise? That's 14 inches per cube, if not then what should I aim for? Also do account for the 2 cubes for the sealed section when determining port area? Or just the 4 cubes of the ported area