barnett - a couple of thoughts about CS2.2s in your room.
The room is wonderfully designed. Congratulations on however you got there. The dimensions are right in the middle of the Bolt Pattern which allows for leeway regarding the contribution of your diffusion panels on the side walls. Also the Bonello Modes stack up very nicely with increasing density per third-octave frequency rise. All good for a musical-sounding space from most anywhere in it.
The picture gets murkier when considering bass, and especially adding a subwoofer. Many of your bass modes fall on whole-notes and intervals which will be accentuated and long-lasting when stimulated. Specifically you have reinforcement modes at 24, 33, 41, 49 Hz (rounded) which fall on notes at A=440Hz. By the way, they fall off-note as the room width acts smaller than 17’. It’s hard to predict exactly how your diffusers affect the functional width of the room.
These modes will definitely be made more troublesome by adding subwoofer(s) bass extension. Those will not be very responsive to equalization. So consider tunable absorption devices to address those issues.
A word about the CS2.2. Bass runs out of steam with a hard ’splat’ when driven hard with bass content. John Atkinson proclaimed in his initial review that the passive radiator and/or woofer was bottoming. He bought and used CS2.2s personally for a few years until the bass problem got the better of him. He is a bass guitarist after all. That speculation turns out to be false. The problem is real, but it fixed itself when I took the crossovers outboard for redevelopment. That ’splat’ is part of an overall veil-shimmer-overload that is part of the CS2.2. It goes away (quite gloriously) with EMF management. If outboarding crossovers is too much, I’m also working on a set of inboard solutions centering on moving the crossover(s) from behind the woofer to the bottom of the cabinet (where they should have been all along.)
Plenty to chew on here. Have fun.
Tom