Volti v Charney v Rethm

I’ve only heard the Rethms at a few shows with unfamiliar associated equipment but they did sound beautiful in the midrange & very pleasing overall but not truly full range & not near as good up loud. They & I’ll guess the Charney’s, while being quite sensitive, are more akin to Quads in sound than to the Volti Rivals that I’ve owned & enjoyed for two years now. 
 

Rivals are very sensitive also & perhaps the absolute last word in gorgeous seductive midrange & fine etched, “hifi” detail some other even much more pricey speakers but can fill a big room like yours w/ live sounding, dynamic, full bodied & full range sound w/ ease. They are much akin to a high quality version of a big Klipsch, JBL or Altec horn loaded system. I too have a big room (23’x 25’x 12’ )  & the Rivals are a ton of fun  & if you like to really nice sound at any sound level but occasionally like to really open it up & wake up your hidden teen spirit ( as well as your wife or neighbors ( forget doing this in a condo)while maintaining excellent sound quality, then definitely check them out. 

... my concern would be bass energy in a large room because of cancellation of the front and back output which are out of phase (this reduces bass by 6 db/octave).

I believe this is true in general,  but as per Ze'ev, not so much with his PAPs as his drivers?/implementation? reduces this typical OB cancelation (exactly how I do not recall). Unless Larryi has measured this cancelation himself or knows a reliable study showing this for the PAPs specifically,  I would ask Ze'ev directly if this is a concern. 

I was impressed with the bass of both the Quintet and Trio speakers I heard because I like fast and nimble woofers that can keep up with the kinds of midrange/treble drivers they use which are also very fast and dynamic sounding.  I also saw that PAP employs the kind of woofers I like which use pleated paper surrounds—those tend to deliver very clean and articulate bass—but because they also limit excursion, they don’t deliver deep bass at high volume levels.  I admit that I don’t prioritize extremely deep bass, so I did not evaluate the PAP speakers I heard for that aspect of performance.  My “concern” was hypothetical and raised as something to look into rather than something I actually heard.

I did see that PAP did employ one approach to reducing back wave cancellation—they effectively widened the baffle with small side supports that extend backwards like the side of a conventional speaker with no back.  This is commonly done with open baffle designs.  It is generally considered better to “widen” the baffle with such wings than to use a wide front panel because of problems with reflections off a wide baffle and diffraction issues.

Aside from the particular demands here--large room and high ceilings—my favorite speakers mentioned here are the Charney Companions with AER drivers and the Quintets.  If corner placement works, I would add the fieldcoil version of the Audio Note AN-E to my personal favorite list.

@larryi - Thanks for your informative post.