Can you tell me where your listening position is in relation to the front (sub) wall and back wall? I'm guessing that your seated in a location that has a room null. The ideal location is 38% from the front wall, followed by 38% from the rear wall. These locations are best for flattest response. 50% is not great, and the worst is being up against the back wall.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85