I'm going to be building an AV-15 sub, and I'm trying to figure out the best way to port it. I've found some good info by searching this forum, but I still need more info. I've read that you can get a pair of Rockford Fosgate 6" flares, and that you need to buy 6" sewer pipe (green) PVC to use as the pipe. Is this correct? If I want to use the ever-popular FP-4 port in a dual-port configuration, I'll need a much longer tube than the one supplied in the kit. What type of tube will work with these flares? IIRC, the tube is ABS plastic and not PVC or anything else I've ever seen at Home Depot. LspCAD has a facility to model flared ports, but I can't figure it out. How are people modeling flared ports? I've seen various "Add X inches" posts for the FP-4, but the number of inches varies and this doesn't help me for the 6" flares. Thanks!