soffit in listening room

my listening room is 14' x 20' with 10' ceiling.  halfway is a 15" x 15" soffit and then columns on both sides of the soffit, same size.  speakers are 3 ft from front wall, listening is on a couch about 3 ft from back wall. should I treat the soffit with acoustic panels in front or back or not?  the listening area is open to a hallway that extends beyond the 20' and has open walkways to kitchen and living room which is an open floor plan. I do have 2'x4'x2" Owens Corning 703 wall panels behind the speakers and 2 bass traps in the corners behind the speakers.  pretty great sound but sometimes experiencing a bit of "ringing"  on the high end. any ideas?
Sure. Cut a sheet of OC703 to make a test panel and stick it up raw wherever you think it might work. Listen and compare. Don't really need 2", for treble/midrange 1" will do fine. Pin cushion pins (the ones with the little round plastic knobs, not push pins which are thicker) will hold them fine at least temporarily and be invisible from a few feet away. 

These panels are best done sparingly. Might start with a couple 12" triangles cut to fit in the front ceiling corners. Then some 10x48 cut to go where the side walls meet the ceiling and/or where the side walls meet the front. These locations are really effective at the kind of noise you're getting without making the room seem damped. There's probably pros with better ideas but this worked great for me.

The raw test panels in this old photo have all come down leaving only the dark fabric covered ones in the corners, so you know what I'm talking about.
very informative millercarbon, thank you!  great looking system, I'll bet it sounds excellent!