It seems that the consensus is the listening chair should be a minimum of 4 feet from the back wall.
Since your topic is imaging and soundstaging, you might also try moving your speakers around a bit. There's an Allison rule that seems to work quite well for speaker placement. That is: (All measurements from the front center woofer driver)
Middle distance squared = shortest distance multiplied by longest distance.
Implementing this rule along with toed-in speakers so the tweeters and midranges are pointed directly at the listener's ear could be an excellent starting point toward obtaining pinpoint imaging and 3-d soundstaging. And perhaps even the ending point.
-IMO
Since your topic is imaging and soundstaging, you might also try moving your speakers around a bit. There's an Allison rule that seems to work quite well for speaker placement. That is: (All measurements from the front center woofer driver)
Middle distance squared = shortest distance multiplied by longest distance.
Implementing this rule along with toed-in speakers so the tweeters and midranges are pointed directly at the listener's ear could be an excellent starting point toward obtaining pinpoint imaging and 3-d soundstaging. And perhaps even the ending point.
-IMO