I used to give my guests the sweet spot and sit directly behind them. Yea I was being a good host but lousy company. It is taken more than a little time and a few bucks but now I have a sweet spot over 6 feet wide so I have two very comfortable chairs side by side" Additional guests sit behind the two front chairs on barstools with back rests.I don't think you really believe you have a sweet spot that is 6 ft. wide. You might have achieved balanced sound so that it is "good" for any listener in that window. But I assure you that when you sit on axis and equidistant between the two speakers, the sound is better than anything on either side of that small area. Just no getting around that.
Oz