The main part has only furniture around the edges; cd rack, big bluray/LP rack, computer desk, treadmill. But I'm just trying for a little more air in the sound. There is nothing between the listening chair and the system, about 9-10 feet.
Have you tried adjusting your speaker placement to improve imaging and top-end sonics? For example, if you have an equipment console between the speakers, move the speakers forward into the room away from the front wall and console. Don't place speakers next to any furniture.
Try firing speakers straight ahead or toe-in at an angle to face your listening position. Try moving them wider apart to create more "air" around the speakers.