@danager : My issue is the bass sounds so much better when I stand up.
I had that experience before too. What I found is that my speakers were too far from the front wall. It took me a couple of days of effort positioning the speakers in 1/2" increments to finally get them dialed in. That includes the distance from the side walls too. The crazy thing is, once I got them dialed in, the bass was nearly uniform all around the room- not just in the listening chair. A good CD for evaluating the bass is Stanley Clarke's East River Drive. The first track has a double tap of the bass drum. When I got everything right that drum sounded good, not muddied to almost inaudible- except when standing up.