"Right now the speakers are positioned about a foot away from the couch on each side — that is, ten feet apart — and back about six inches from the front of the couch, and toed in significantly, so I can see down the horns from my listening chair, which is maybe 8 feet from the front of the couch."
Brooklynluke have you tried positioning the speakers slightly in front of the couch? Considering the dispersion pattern of the speaker in the above position, sound must be hitting the front edge of the couch. Sound from the tweeter may not be affected, but no doubt, sound from the woofer is affected.