Just to add a bit of info, I'm the owner of the above system. I largely agree with Keith's assessment of the impact of BACCH with these speakers.
A few points that might add a bit more context.
Firstly, the speaker positioning (in the corners) is a combination of necessity - they are rather imposing beasts, and recommendation. The manufacturer recommends just this placement.
Thanks both of you for sharing. The room looks like a tough challenge (asymmetry, corner positions, long distance ...).
We have to manage expectations, where DSP has its limits, even with more calculation power and algorithms:
First, DSP can equalize a speaker quite well TONALLY to fix problems AT the SOURCE. These effects on the sound generation can be heard immediately. You can also shape the wave-front by DSP'ing multiple drivers (cardioid bass or line-arrays).
Room correction and crosstalk elimination try to treat problems AFTER the sound generation by employing pre-distortion.
There are limitations to this, you can't realistically get rid of cabinet vibrations, reflections, standing waves and echoes. You can REDUCE room modes and cross-talk in SINGLE locations at SOME moments in time.
Example: In one room the PSI AVAA active bass trap clearly elimated annoying room modes at the listening, in my room it did nothing noticable and introduced more boom in another location. A normal bass trap for less than a quarter of the price worked much better (but is bigger of course).
What the pro-DSP fraction is simply saying: before spending another 10k on new electronics and speakers, first optimize your room/speaker position, choose a system you enjoy and then try DSP for touch-ups (Dirac, Acourate, BACCH etc.).
Different speakers introduce different problems. DSP keeps the sonic character of your system and improves the result.