Multiple subwoofers work wonders

Adding a distributed bass array was the single biggest improvement to my system.

And, looking at your system page, that is a very impressive and flat frequency response you have achieved. Totally jealous.

Thanks. It's taken me a long time and is still a work in progress. Cannot stop tweaking.
One of the more interesting phenomena I've noted is that while I have been able to achieve an even flatter frequency response, the room modes were far worse. It's kind of a balancing act. 

@tcutter I see a lot of visual symmetry in the room which is quite pleasing to the eye. Did you make some aural compromises to achieve this? Or does it just happen to sound better AND be visually symmetrical?

Little physics, little aesthetics, lot of luck. Anal retentiveness probably helps. 

+1 distributed bass array (James Romeyn's version as well)

not to derail the topic, but I gotta ask: how do you like your Vinnie Rossi pre w/ your XA60.8s???