RPG Skyline mounting on ceiling

Thanks, Bob. You could temporarily try absorbant matl in the corner behind or on the side wall next & slightly behind the speaker. For the corner, try covering ceiling to floor, if you can. If this helps, you can then look for the appropriately cosmetic application (tube traps usually sound better than they look-:).

Gregm thanks for the great idea! Also much appreciate your referral Kitch. That corner has always bothered me as there is a curtained window in the way. I never even thought of mounting "on the sidewall next & slightly behind the spkr." that's just a fabulous suggestion.
This is such a perfect example of why we should participate in the forums; you never know when someone is going to come up with a great suggestion / solution (to my offhand comment) & I wasn't really even seeking answers, so this is such a pleasant surprise! thanks again y'all!

Enjoy the tunes, everyone!
Greg