I see it's 5 meters away. Sensitivity is 90db at 1 meter. 105db is the dynamic goal(30 db above THX) To reach that we much use 2, 4, 8, 16 watts if your speakers is the full 5 meters. Now we need to tack on the distance. 32,64,128,256. You need 256 watts(too high for receiver and speakers) on those speakers to get the full dynamic range. If you can move the seating and/or speakers a combined 1 meter closer you would be golden for THX dynamic needs.