Hi my first look at treatment, I have a dedicated room of modest size. 3m x 3m tapering to 2.5m at the seating end. Bigger would be nice but at least it's my own space. Floor is raised wood with a void above soil, walls are stud work plasterboard with acoustic insulation, ceiling is at 2.5m with plasterboard and acoustic insulation. This is built inside a timber frame barn so has another wall surrounding it with a void. Speakers are 15" bass drivers in open backed box ( open baffle ) 200hz tractrix horns with compression drivers and raal ribbons. Tri-amped all valve amplifiers. Listening distance is about 2.5m. Surprisingly it sounds as good as my old room with solid walls and floor. I also run deqx as crossover with room eq though not used. Question is would there be a basic room treatment package that if nothing else wouldn't make it sound worse. Would a diffuser on the ceiling be a good idea regardless of the current sound quality