I should make a few clarifications in my message.
First, the sofa was actually a Futon. Are those not mainly constructed of cotton type material?
I believe that the dipole nature of the Maggies does not work well with corner bass traps. As stated earlier, my existing bass traps at the front of the room are about one foot behind the woofer panel itself. The speakers are about 5 feet off the front wall.
They say that the front and rear wall should be different from each other in material construction or absorbtion, diffraction qualities. That is why I thought if I covered the wall at the rear of the room with all these DIY panels, that I may gain something. That said, the rear wall in the room has a "L" shape jog to it. Maybe the lack of an even plane wall at the back already breaks up the sound alot????
Hope that helps clarify some things.
R.