Easy to drive, outstandingly natural sound from 40-50 Hz up.....AN-E, O/96, others?

Absolutely ! However, K horns need corners. The Lascala does not, and benefits from a pair of subs from 50 hz down. I have been a Klipsch Heritage fanatic for 50 years, and when I get done with a pair, none of the nasties are present. Just beautiful, realistic sounding, fun and involving performances, right in your listening space. 

@mrdecibel 
I could do corners, or not, so either Klipschorn or LaScala are possible, and the room is big enough.  What do you mean by;

"when I get done with a pair, none of the nasties are present"

Are you talking about making modifications you have learned over the years, or do you have a business to modify/improve Klipsch Heritage speakers?  Pardon please if I have missed something earlier.

Big Tannoy - the legacy arden do 35hz - 30kHz and an easy 93db driving speaker.
But O93 should be cheaper and easier to pick up in the US (tannoys in UK relatively cheaper $7000 new for the Ardens) and I would have prob been keen on them and Audionote AN’s as alternative.
Think all 3 are ones to lose yourself in music with.

Take a serious look into the Spatial Audio speakers. Their entry models have a coaxial compression driver (midwoofer functions as horn like Tannoys) with 93db sensitivity. Zero horn "honk." The nominal impedance of their Triode Master M3s/M4s is 12ohms.

I’ve heard some of the other speakers mentioned here, including the ANs and Spendors, and the performance of even the entry-level Spatials is on par. I was almost deterred by their pro-driver compliment but one must keep in mind they are custom spec’d by Spatial, not off-the-shelf units. They can produce high SPLs with just a few watts but are robust enough to power an auditorium. 

I’m very particular about tonal balance, hence my being a fan of Spendor Classics. The Spatials produce a nearly identical midrange (a little better honestly), a bit more sparkle on the top end and superior decay. Never fatiguing. The bass is incredibly defined and better than anything else I’ve had in house. I have their smallest model in a rather large room and the bass impact/slam is still very good. Best thing about them is you can get all this performance for 1/2 the price of comparable ANs or Spendors. 60 day in-home trial.