My room had a bunch of openings and a fireplace. It is carpeted, with six absorption panels and one of those bamboo folding room dividers with a heavy comforter hanging over it on the right side where there is no wall. The fireplace glass is covered and one of those absorption panels is in the first reflection point on the left wall. I bought a couple of 18”, triangle bass traps that are in the top front corners. I also have a couple of large pieces of hard foam board that I occasionally move around to see if I can hear any difference.
With all the openings, a wife and two dogs, I think I have done about all I can do to the room and I am really happy with the results. Even with the dogs sleeping and snoring on either side of me. 🐾🐾