One thing you do not want to do is sit in the middle of the room, you will have bass nulls for sure.
Have you tried the sub in a front corner?
The very first place I put it was about 1/3 of the way back from the front wall, on the side wall as it makes a great end table for my loveseat. I wasn't getting much impact which is what made me start this whole process in the first place. I figured this thing was overkill and I could place it anywhere and get good results, which I am clearly finding out, is not the case.
When I did the sub crawl, there is no impact near the front wall in either corner, at all.
