Sweat spot? Sp. placementt again


I get better sound standing up, rather than sitting, at the listening position. Anyone encountered this? Pls read on before you bash...
The listening position is two feet from the listener's back wall which is damped with wall carpeting.
We pooled resources with my partner (she's from down under: they hear things diffferently there, so she says) reaching an optimum positioning for our Gen Vs, following hints from Redkiwi's ("speaker placement") posts -- thanks everyone!
The room has an asymetrical listener's back wall, with a round fireplace on one corner and a 7ft opening at the other -- 12ft wall in between. The ceiling is 8ft high, room length ~25ft.

We tried listening closer to the speakers -- but, no cigar. Tried a higher chair too! -- ditto.

Any ideas?? Thanks.
gregm
Please let us know, how things went, after damping the first reflection point on the ceiling. This could well be the culprit, especially that point, where the tweaters start reflecting.
Phase differences do not have a noticable effect on the quality of the sound itself. They do affect the stereo image which can be blurred or cause effect known as 'two islands', you hear nothing but extreme left an right positions.
Gregm, I wish I could help you this, but I had a similair problem and without some costly changes and treatment, I just could not get my placement right with my speakers. It drove me to the point where I'm selling my system. IN hopes of buying a new house in a few years and trying to build a specail room just for listening.
...were so encouraging it's scary. Thanks everyone!! I used two 2"x2" table matts for a quick experiment, placed as per Avguygeorge & Detlof above. Bingo! details have become more palpable, female voices (I tried contralto, and jazz) are now better outlined -- AND the stereo image is more focused. Standing up, however, still gives a slightly different "hue". I will experiment more during this w/e, and hope to get back to you with more...
BRIWEVE, give it a last chance: dampen 1st reflections on ceiling and side walls, just TRY it.