Macklessdaddy
10+ year member
CarAudio.com Elite
he was joking manzzztuning a box requires calculating port area from pretty big equations. Usually it is best to have some kind of program find it for you. But it all has to do with port area which is the cubic feet of air that fills up the entire port. Perfectly sealed boxes are achieved by accurate cuts. Although if you can't make a perfect cut caulk will seal it up. I dont know what "custom" sealing is? I guess technically it is all custom besides pre-fab.