Hi,
As for all audio speakers, the common recommendation is . . .
The proximity to the rear wall is only a minor concern because of the ports. You could be within 2 inches and that would be enough room for the ports to breath. Putting any speaker close to a wall, and even more so close to a corner, will give you quite a boost in the upper bass region. It does not matter if the ports are in the front or the back or if there are no ports at all. It is one of those things you just have to try and if you seem to have an overpowering and muddy bass then you need to move the speakers away from the wall a bit.
