Is the conventional wisdom that sub woofer placement should be on the floor? I have a nice out-of-the-way spot atop our armoire. Putting it here would put the feet of the sub on wood, rather than carpet. It would also keep it out of the way of my 2 year old, and vacuuming ease and asthetic are also good reasons. The top of the sub cabinet would be inches from the ceiling. Of course I could experiment, but I'd like opinions please. Thanks!