My favorite loudspeaker finish is the same as my favorite automobile finish: hot rod black, the color 1950's hot road enthusiasts (including guitarists Jeff Beck and Danny Gatton) use on their rods. I painted the enclosures I made for my Rythmik and GR Research subs with the rattle can paint offered by tractor company John Deere. The black color they make exhibits a very cool (to me at least) sheen half way between flat black and satin.