Open Baffle On-Wall mini speakers

I am designing an open baffle on - wall speaker system, as previous attempts at enclosed speakers did not work out that well. I may add a subwoofer in the end or use equalization.

At a distance of about 30 cm from the rear wall is where it sounds best.

This is an inspiration. http://www.diyaudio.com/forums/mult...design-using-seas-8-tang-band-full-range.html

The other threads dont go anywhere really most of them.

Are these dimensions more or less ok for a 4 inch speaker?