maybe going for a nice metal look to the box?? IMO it would look better having a metal looking back to the box over a wood look. But i think a mirror would look better that way you can see the back of the subs.Originally posted by fantomas you might be able to glue a mirror in...and maybe drill the sheet metal in with 1/2" screws...just short enough as to not go completely through the mdf. why would you put sheet metal in your box..?