Interesting... will give that a try. Are you thinking "close to the speakers" or more like what "on the walls" would be if I had a wall on both sides ?
Surprisingly the difference was not all that subtle... imaging went from "OK I guess" to "quite good" with just that one change.
I am going to try to either build or source some kind of diffusion over the winter. I picked up a calibrated Dayton mic to go with the 2i2 A/D converter so will try to get REW running before I mess with room treatments much more.
That way I can imagine I see changes as well as imagining I hear them