Hey Mike,
They are MDF cabinets, with 1/2" round overs on all sides. I painted them with eggshell simigloss house paint. I would do a coat then sand, do a coat, then sand. Probably eight times until it had an orange peel look and the seams were gone. Same with the centers and surrounds.
That is one tall driver in ur pic, what is it ? What size ?
Kg
PS I thought my Tumults were tall !