I just bought two twelve inch rockford fosgate P3's and I was thinking about making a ported box for them. I have made sealed boxes before but I have never made a ported box. I mainly listen to rap and music of that sort so I was thinking I'd like the ported box better. Anyway I can make the box I just do not know how to make the port. RF recommends a 4" diameter 11" long. I did not know if I should make this type of port out of pvc pipe or if I should make a square port or if I should make just a vent. I do not know how to figure out the lengths or sizes of the square port or the vent so I was just wondering if someone could help me out with that so I can figure out which will fit in my oddly shaped box best. Thanks