I do consulting in sound and vision. I had many stereo highend systems. I did now have surround because the quality was not good enough want I wanted. Until roomcorrection. It breings surround to a level which I am happy with. Without it I would not want surround even for free. Wenn you have highend systems 3 dimensional sound is a pre, or you miss an important part in realistic sound. That was the reason why I sold my Nautilus 800S. B&W is very poor in 3d imaging. Wenn you want to go further in quality you have to stop with some brands. Classe is a brand what is very capable of depth. But without roomcorrection you never get that level which is superior. In the past I owned the Pass Labs XA100.5 and XP-20. Now I use the Pass labs X250.0 and Onkyo PR-SC5509. The grazy thing is; I have an extreem 3d image even with stereo. Onkyo ( Integra) is the only brand which can play deep behind the speakers. Brand like Arcam, Marantz, Denon are all 2 dimensional. I sold these brands for many years and I tested them many times. For me it is as simple as 1 and 1 is 2 what it is capable for in quality and properties. With Audessey Pro I got a level what I never thought it would be possible in surround. Focus on instruments and how clear a voice sounds go's more easily than wenn I used the XP-20. There is one limitation. You need to know a lot about sound to use Audessey pro. For most consumers it is not an easy system to use. I measure at different hights than Audessey does. But at the end I get an higher level in quality they get. Wenn I play stereo my sub is fully stealth with the other speakers. These days I set my sub to 120hz. This sets everything to an higher level. You need a subwoofer without bass reflex system and a big speaker unit only on the front side. Alle other kinds of subs I tested all failled in tests to become fyll stealth. I hate wenn a sub is to slow and not fully stealth. Most subs you can throw in the garbage bag. Only with a good roomcorrection system like Audessey pro your speakers incl. sub become one. Wenn you do not use this you always can easily hear the flaw's. For me it is perfect sound or nothing. There is never a solution in between.