Hey,
Just stumbled in here.
I'll put my two cents in for the Ronin and other dipolar speakers that do not radiate HF to the rear, but radiate a larger than average midrange to the rear <1300Hz.
I think light absobtion and mostly diffusion on the rear walls works the best. Somthing like what bpape said above. Unlike Maggies/Soundlab etc, they do not radiate tons of HF to the rear. Speakers that do this IMO, absolutely require some absobtion behind them. Without this, I find them to get confused sounding with images that shrink into the speakers, thin tonal balance etc.
With speakers like the Ronin that only radiates 1300Hz on down to the rear, I find that only minor room treatments are necessary. In my room for example, I have simple rough panneling on studs (think 1970's) it is very flexible in that it is only 1/8" thick and diffractive at HF due to the roughness of it (think stucco). I find that this is all that is necessary in my particular room. In rooms with more rigid walls (drywall, plaster lath etc) and closer placement, things like record/cd holders furniture etc, help to break up the rear wave and in most circumstances provide a better experience. Pure absorbtion works too, but again, IMO not as well. I have used large sections of 6-8" thick 'pyramid' open cell foam and did not like what it did. It was heavy treatment, but I felt that a bit of the dipole midrange magic was lost and things became a bit overly focused. This is the same feeling I get with standard boxed speakers in overly treated rooms.
Also remember that some reverberant nature to the room is desired, it just the quality, quantity and direction that these reverberations come from that matter
.
With most speakers that I have encountered over the years, most 'lived in' spaces will sound pretty good by themselves. More modern, clean rooms can sound good with a little creativity. Of course the major exceptions to this are things like cinder block walls, hardwood/tile floors, and large expanses of glass.
Maybe this helps ?!?! It just made me think more and ramble.
Have a good one guys,
Paul
