If your room, which is obviously a sonic nightmare and is basically an echo chamber, didn’t work with the Dynes or Sonetto it’ll only get worse with the 705s that lean even brighter. If I was you I’d seriously be looking at some kind of digital room EQ if you can’t do anything to treat that room. Can’t you at least put down an area rug? I’d think even just doing that might improve acoustics quite a bit. Just my $0.02 FWIW, and best of luck with this very challenging situation.
B&W 705 S3 with bad acoustics
We Recently moved into a new home that has terrible room acoustics, 12' ceilings, tile floors, glass window walls. Open floor plan with no possibility or room treatment. I've never owned B&W speakers curious if they will glare in a very resonate room. Previous tried Kef Rs meta, Dynaudio special 40 and Sonus Faber Sonetto w/ Rel T9x with no luck. Paird with Hegel h390. Auralic streamer.