sub shakes upstairs, but virtually nothin downstairs

[dzirkelb]

I just set up my sub / system (SB12-Plus), and I obviously have it in the wrong place because downstairs where the system is, I feel nothing; however, it shakes upstairs.

Here is my room layout:

Next to the speaker to the left are stairs that lead upstairs to a large open area, to the right is a hallway. I am assuming this is the problem. The front speakers / tv are to the right of the sub about 6 ft.

So, my question is this...should I place the sub in the back right corner facing in to the middle of the room where everyone will be sitting? In that corner there is no open areas.

the back left corner is a little more set back as the room opens up a couple more feet to a fireplace, so I am guessing that is not the correct place.

Any help would be greatly appreciated.