bigjohn, yes I am putting it inside the cabinet. I know it's not the ideal, but it's a built-in entertainment center with a space under the TV. There are doors, but they are covered with speaker foam. I'd attach a picture, but I don't know how. Plus, I really don't have anywhere else to put it.

With the sub on its side, there should be plenty of room aound all sides, plus the "vented" doors in front of it.