i dont know much about boxes but i built my first one today...i got 2 150w Advent subs and a 300w Jensen amp. I putone porthole in my box that made out of PVC and I'm hoping it works,I don't see why it wouldn't..I havent tested it out yet but when I do I'll let ya know.. PVC,porthole, they're both plastic so I'm givin it a try.
