Axiom Home Page Forums General Discussion Home Theater Sub concern

One unavoidable difference is that "upstairs" floors vibrate and "basement" floors generally do not, so that will make a difference. You can get around this to some extent by building a small riser for the seating, and to a greater extent by putting the sub on the riser behind the seats.

Other than that -- placement makes a huge difference. Did you post the room dimensions, or just total volume ? EDIT -- ahh, here we go -- 20 x 20 x 7.

Any chance your seating position is in the middle of the room, particularly between front and rear walls ? If so, try moving the sub immediately behind the seats.