Tried my best to use WinISD and SketchUp correctly, did some math, and came up with this. First time I have used either program It is for a pair of old school MTX ThunderPro TP1540 15's. I was given max dimensions of 40L x 40W x 13H for the install. From what WinISD said, the box should be just under 3ft^3 per speaker. Tuned the port to 35Hz. Any thoughts? Changes I need to make? Suggestions? Improvements?