If you mount it low, you'll need an external speaker.
That's made from 2 pieces of sheet metal, carefully cut & bent by hand. 1 is screwed to the roof; the other hangs on 2 screw heads in the first, and on the w/s upper trim. It has 1/8" foam padding glued to it, and cheap "duck canvas" on top of that, both from WM. The wiring comes up the A-pillar from the fuse block & the antennae wires go thru the roof down the back of the cab along the bedrails to the bracket on the back of the truck.