Did you try to drive them with a more powerful amp? You might not except such a rough comment, but I used to drive mine, which are also two feet from the wall measesured as you desribed, with a MF 3.2 power (150 watt) amp and the room was booming business all the time. Swapped the amp for its bigger sibling, the 308 ower amp (250 watt), allowed the bass to become tight, detailed and controlled, with all boominess having disappeared then. This also induced the midrange to open up further and the total sound got amazingly good.
Cheers, Erik
Cheers, Erik