Ok guys I need some major help I am trying to build a ported box for one alpine type R twelve dvc 4 ohms. I can not figure out the size of the port and I have read the JL audio tutorials a thousand times but can find a manufacturers suggested port size to figure it out. I am going to slot port it if I can get some hints. Can some one point me to a sight tell me what they know or give thier email so I can send them my dimensions and get some advice thanks.