[Face]

I've heard multiple setups with Polk's SDA technology.

If you can set them up in your correctly, they sound pretty good. The soundstage wraps completely around you and images are well defined, even well out of boundaries of the speakers. But, the speakers need to be placed against the wall with no toe, the listening position must be an equilateral triangle, which usually puts the sweet spot in the middle of the room, and most models require a common ground amp or an isolation transformer connecting the two speakers to each other.

The technology is still used in their surround bars, which again, vary by room and model.

I'm very familiar with their schematics and how they work, when I'm done with my laundry list of DIY projects here, I may try to build a pair using high quality, modern drivers. Maybe incorporate some baffle step compensation so the speakers may be placed a few feet into the room too.