Heavy drapes over those ugly panels, hides the utilitarian and adds some dampening as well.
Edit: forgot the where to put them part of the question which is ultimately unanswerable without know what you are doing and the details of the space including what is in the room.
Edit: forgot the where to put them part of the question which is ultimately unanswerable without know what you are doing and the details of the space including what is in the room.