Three and a half years have went with me greatly enjoying the CNO Grandes I've built. Family moved house last year and I'm now the proud owner of my own work/audio room of about 28m2, 4.6*6m. While still immensely impressed by the CNOs, thoughts went wandering. I wanted to try something different, something big this time, so the question was TL-2 or OBL-15? Although I fully believe the TL-2 to be a very good loudspeaker, it does not strike me as aesthetically pleasing and, more important, different enough. So, I choose to build the OBL-15. Kit arrived in may, but it took me until now to get it finished. Although it looks sort of simple on first glance, I'll say I've spent as much time on them as on the CNOs, all this color work takes time. Yes, I opted for a red my friends call 'fræk' instead of veneer, and I'm very happy with the result. 
Yes, they are big, but WAF does not rule in my room.
How do they sound? Well, I have it with describing sound as you do. With that said, coming from the CNOs, I'm absolutely amazed. They play differently, as you also try to explain. The scene is broad, the bass is astounding, and mids and highs are where I expect them to be, CNO level.
They, despite their size, nearly vanish and just fill the room. To my taste it is a definite upgrade. And the high sensitivity plays into my tube amp collection, although the CNOs did quite well in that regard, too.
So, many thanks again for your work and designs.
Regards Rüdiger
 
PS 1: Amplification on one of the pictures are 2 pieces Bruce Heran design OddBlocks, class A monoblocks, running 2 KT77 each for about 17-20 watts (up to KT120 possible). Preamp is a ForeWatt, also Bruce Heran, mostly run passive. They play the OBLs frightening loud!
 
PS2: No worries about the walls in the 'mockup' picture. Taken short after move in last summer. Problem has been solved by another project involving me digging 20m3 dirt out...
 
PS3: I can only reiterate other builders comments: If you have the space, give them a try!