Funny about the advice from Rel. I respect them, love their products, and suspect they were not just trying to upsell you to a swarm. Most of us here don’t have the luxury of trying things out for free. So, we read articles, ask for advice here and when enough evidence piles up we spend thousands for things we may have not heard. So, I entirely understand the comments about consulting Rel or looking at graphs… trying to understand in the abstract because many of us can’t easily/cheaply audition components in our homes. If I could invite you to my house I would so you could hear. I can’t so my opening entry in this thread is another piece of abstract advice: some guy you don’t know claims he had a transformative experience— a person who has little credibility compared to folks at Rel. I get it. And I can’t promise that any 3 subs plus any 2 mains will yield the same result. I can only say it happened in my system and might In yours if you try. Would I spend thousands to buy a new sub in the hope of achieving a holographic sound? No. The results are too system dependent. But if you have a third sub, try it out because you know for a fact that for one person something special happened.
Fun/long article about subs sited by another agon member: http://www.soundoctor.com/whitepapers/subs.htm