+1 @kofibaffour get a mic and use REW to analyze the room. You can send the result files to somewhere like GIK and they will make recommendations.
Room treatment
My listening room sounds overly dampened, and I want to look at options for making the sound brighter. The room is 4 meters by 7 meters by 2.75 meters. Two walls are mostly covered with bookcases, and two walls are partially covered by curtained windows. The floor has wall-to-wall carpet. What should I consider?