Absolutely. You don't need a divider in the box either but i do recommend stabilizer boards or bars inside the box from wall to wall front to back and top to bottom to keep the larger boards from flexing. Box flexing=sound loss.
and instead of adding anything useful, he just said "agrees"...that, my friend, takes some work //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif