I am looking to fabricate a new box for my current sub ( as it looks like I am not going to get a replacement set before I go to school and once I do I will not have money to do anything with ym system untill next summer.

So, my goal as of now is to create a ported (I dont want to sacrifice those nice low end rumbles) box that will take up very little trunk space in the back of my Ford Focus ZX3.

My idea so far is to make a box that spans the entire width of my trunk, but make it short, so basicaly a 90 degree triangle butted up against the back of my car.

The difficulties come in when I have to deal with a spare tire that sticks up above the floor level and I want to flush mount the sub so that i can put a grille over it and not worry about damaging the sub if I put my backpack on top of it or something.

This is a rough sketch of what I am looking at currently.



What I need to know is how to port it properly, and if there are any critical flaws with the design. Also are there any programs that I could use to create a model of this before I make it so I know that it all will work?

Any and all help is greatly appreciated.