Stroms, welcome! I have my front CBM-170s on shelves in my entertainment center. While it might not be the optimal place for them, I haven't had any issues. As long as you have enough room for the ports to breathe (and from the dimensions that you gave, I would say that you do)you should be ok. Also I have my speakers as far towards the front of the shelf as possible. One more thing - I have a couple of books on the shelves to try and minimize any echos.