Ok, I have a box devided into 3 seperate parts for 3 12" "Volfenhag" subs (wouldnt recamend =P) They are running at 500 wats each, and I was thinking about porting my box (well, all 3 sections) I was thinking juz a whole w/pvc in it for a port, but I dont kow how big the wholes should be...