Very neat speakers... I've done some woodworking / finishing, and the best way short of veneering to finish MDF is to spray [not brush] a shellac sealer on the exterior first... A few coats are in order to really seal the pores... Then you can topcoat with a finish of your choice... I personally like a spattered paint finish, which is also sprayed on... Looks professional in all respects... One thing I'd watch out for is where the butted edges meet and are exposed to the exterior... These should be filled with some kind of non-cracking wood filler, then sanded well before sealing... (m.)