I have 2 of these MBM12-LX:
https://www.diysoundgroup.com/bundles/midbass-modules/mbm-12lx-kit.html
I have them pointed directly behind me inches from the back of my couch. Gives me a huge kick in the chest! I am going to get 2 more for up front... Should I face the next 2 at the seating position or towards the front wall? They will be just inches from the front wall.