first off thanks to bcarpenter for helping me with the box design... we came up with 31x15x16 widthXheightXdepth for external box dimensions for a ported box. widthXheightXdepth... we also got the vent size of 2.75 x 13.5 and are tuning is somewhere around 32 hz. the thing we cant figure out is the port length.. we came up with somewhere around 40-45". After that he could no logner help me. another thing i dont kno how to put 40-45 inches of port lenth. 31+16 equals 47 and yea not sure what i would need to do.. ne help or pictures of there port length..; im not sure what port lenth really is. i do but a very vague idea from what my jl audio specs sheet tells me. so if u can please help. my aim adress is bigjonny33 if u want to im me there.