here is a new box i built, it still needs some fine tuning but gets very loud with about anything you put in there. right now i got 2 elevation audio comp 10"s that retail at $99 bucks each and i get door flexing withit. its a wickedone box design. its a pain in the ass to make and you must be a very good box maker to make this. it takes almost a sheet and a half of 3/4"mdf and the size of the boxes is almost 12 cubes. it can get very loud with low dollar subs so i would say it would get really really loud with some high dollar subs.