sunnyjim,
I understand your perspective. I seem to remember feeling similarly when I heard the 1.6. It lost too much of the warmth range.
The 3.7s are both super smooth (not peaky or hashy), and I combined them with Conrad Johnson amps, in a nice sounding room. My audio-reviewer pal who said Thiels at audio shows had previously made him want to run shrieking from the room, did a 180 once he heard them in my set up. I have tinnitus and bright or peaky sound bugs my ears way before they bother most people, and the 3.7s in my set up are the smoothest, least fatiguing speaker I’ve ever owned.
And fully fleshed out in the midrange.
So what I heard with the Harbeths was a very clear, well controlled sound, with that Harbeth lushness in the midrage for vocals and other instruments that reside there. Beautifully balanced speakers. But perhaps because of the "lively cabinet" design philosophy they never quite disappeared sonically. When I played the same tracks on the Thiels it was amazing how, even being far bigger speakers, they utterly "disappeared" sonically in a way the Harbeths never did. Everything cleared up around instruments, and the sound was simultaneously as detailed or more detailed, yet more solid and "there," while, amazingly, also sounding more relaxed and organic in rendering detail They just seemed to do what speaker designers always seem aiming to attempt: sounded more "real" in all the right ways to my ears.
The Harbeths did have a certain "rounded, fleshy" character with vocals that I haven’t quite heard from other speakers, though.