Quote Originally Posted by nightflier
I tried several different speakers last night because I believe that how far one can move to the left & right w/o noticeable audible effects is largely a funtion of the speaker, more specifically the dispersion of the speaker. To a lesser extent, the size of the room and the sound treatments will also affect this.

My Klipsch RB5's for example did sound different when I moved just a little to the left or right on my couch. On the other hand, my Polk RT600i's, which are an entirely different type of speaker, required about 3 feet before it became noticeable to my ears.
I have to ask, nightflier, how large is your room, how far are you from the speakers, and how far apart are they spaced. 3 feet isn't impossible, but necessitates such a large room, or a lot of imagination to work right. My experiences with the RT600i's haven't been nearly as favorable as this. Even speakers with the widest dispersion would suffer a tremendous shift in center image 3 feet off the center...there's one sound arriving far faster to your ears than the other, 3 ms is a long time in the audio realm....the precedence effect kicks in...you either get an echoey effect or massive tilt towards one speaker.