Well I measured across the top for the top measurement since it is straight across. I then cut the first piece that will be the front piece with no curves(rectangular). Then I took cardboard and marked it an trimmed until I had the pattern, I then transfererred that pattern to each end of the front piece and cut it with a jigsaw. I boxed the top and the bottom, the sides and back are open, except where the sub speaker is. I mounted the speakers and it worked fine. As you can see if you go no further down then the level where the strap attaches the tops will slide right in under the box, I do that all of the time. I covered it with marine grade vinyl after I cut the holes for the speakers. It actually slides in and out and is not permenantly mounted, it has to go in at an angle on one side first then the other so it holds intself in the car perfectly and can not move unless I want it too. I measured the inside of the box and hunted around on line and found an amp that would fit and mounted it longetudinally inside the box as well for a sub amp. The 6 inch sub speaker is a marginal performer, but does exactly what I wanted it to do. It only took me about an afternoon to build it in my garage. I hope that helps.
Last edited by Okie81; 10-10-2010 at 12:09 PM.