I am looking to build a box for a super-cab 2005 f150. I would like a down firing one with one 10 inch sub. Searched but was unable to find specs or dimensions to built one to. I am good with building things but not with calculating dimensions. Thanks in advance.

 

Try this, should be able yo base just one sub using the large portion of the seat. just remeasure to confirm it will fit.

https://www.f150online.com/forums/3552167-post4.html