I find the sweet spot quite small for stereo, just right for one person or two very friendly ones. Moving to the side still sounds great, but you lose the "phantom speaker" a few inches from the center position.

For HT however, all seating positions seem more equal. I have dipoles mounted to the side and above the listening position, no closer than 5 feet to either edge of the couch, and the whole couch offers excellent sound in 5.1 or 7.1. I perceive a "sweet bubble" when using the system for HT, that surrounds the entire listening area.

950/M200 7.1, Rocket 750, 200, 300, 150, JBL PSW-12 sub