I have 3x era 300s and 1x sub gen 3 in large entertainment room for music listening only. 2x Eras are connected in stereo on one end of the room and 1x era 300 is paired with the sub gen 3. the room dimensions = 5 meters x 8.5 meters x 2.5 meters (height). My issue is to do with bass since most of the bass is on one half of the roof. Do I need another sub or is it a placement matter? Please help