Bill
I have been moving the speakers around and positioning them all over the place, stuffed pillows in the corner, checked the phasing, tried my other set of Kappa 9's etc. and no matter what I still have this real boxy sound especially from the right one. You can stand 2 feet in front of it and hear it. It sounds like it's coming right from the speaker but must be room interaction. The Kappas also have more bass than in any other room before. So is this a floor to ceiling bounce resonance, or it the corner, or the ceiling corners or a little of all?
mg
Part of this is room construction and part of this is corner loading. It can also be that your system audio chain is having a hard time with the new environment.
Bill
Would the corners and XLT in the corner be enough to trap out the boxiness?
mg
The RoomTune would balance out the room buildup coming from the room's seams and corners.
Bill
My last place had a sloping ceiling that went from 8ft to 11ft and I didn't have this issue at all.
mg
I just moved from a place that had the 8-11' design as well, loved it! I had a system setup in every room. Very easy to tune.
Bill
What is the frequency range that the pillows affect?"
mg
RoomTune is a full range acoustical barricade system.
Kappa's can be touchy, after you treat your room, you might even need to have a Speaker Platform made for you so you can adjust the transfer between the speaker and floor. Your going to be able to get things straightened out but it might take several parts to fix it. From what I'm looking at I see both mechanical and acoustical symptoms. Good news is it sounds like you don't have anything missing in the sound. With Kappa's if you have something missing it can be a real bear to create, but being that you have the opposite going on, it's more a matter of foundation and room response.
If you want to test the waters with RoomTune you can get a couple to use in that troubled corner and let me know what your hearing then we can take more steps.