once again i never said I knew all the answers to my questions. I told ya'll i don't know shit when it comes design or specifics, Read my post! and secondly all I was trying to due was explain what I had (sorry I didn't know the proper terms). Just from a common ear it is easy to determine that the certain kind of setup its the best sound responce when it comes to clarity and crisp bass. Now if you want to get a loud rattlefest and a little deeper bass on the outside then conventional boxes are for you. But if it will sound like you only have 1 low end 10 in the trunk, when sitting inside your car. Third yes I mean custom like you go to the shop and they built a specific box for your setup and car. Out here in the Bay area all we have are Car audio shops everyehere, but like i said I never knew anything about the math behind box building, so I never asked the several different installers i've had what the box was tuned to.