reply back from monoprice:
In regards to your inquiry, unfortunately we dont have a box size specification for our speakers as many of our customers install them with out a box and in rare occasions such as yours might need one. We would recommend that as long as you do have 1/2 clearance from side to side around the back of the speaker that would be enough clearance for the speaker to have proper sound. We have included speaker stats for the item PID 4103 and is in PDF format.
Bill, can I email you the speaker stats to see if you can understand them...I know I certainly don't