That is a good point. What is your take on diffraction in your speakers for home use. The moulded horns look like they would perform better than the SH50 as far as diffraction goes.
Diffraction..
I would say the place to start is the baffle step frequency.
So lets say you had a big flat baffle with a tiny acoustic source at the center.
You find that at up high the sound radiates in a hemisphere, 180 degrees (meaning the -6dB points in the lobe)
BUT at some frequency, the radiation angle increases and eventually wraps around and radiates 360 degrees.
So starting high up, the baffle is large enough to confine the radiation angle to 180 degrees and HOW the sound can radiate past the edge of that baffle and not wrap around is exactly the same as how a horn can have a fixed radiation angle and the wave continue on it's way.
How is by forming a smooth curved wavefront that gradually expands exponentially until the geometry of the pressure distribution allows it to proceed free of the physical boundary.
All is well as long as the boundary is large and flat. Rather, as the wavefront expands and before it is large enough to radiate on it's on, a discontinuity in area or obstacle and several other things can cause a radiation from that point. That new and slightly delayed radiation causes fine structure comb filtering which can directly conflict with ones pina and HRTF's subjectively harming the stereo image and producing clues your ears can triangulate on as "sources in that location".
In other words diffraction is just one thing that can be especially harmful and when it's within the first 8 or 10 inches from the source, seems like that is most important NOT to have re-radiation.
Now the reflected sound off the room side walls is another issue next.
A horn particularly a conical types are or can literally be a fractional space condition, for a horn, that point where it stops confining the angle to X is 10^6 / horn angle / horn dimension inches. Each octave below that, the angle doubles.
I agree about the SM-60 horn horn shape, there are things you cant do with Baltic Birch haha.
The polar plots for the new speaker will be essentially the same the SM-60f (a little different down low) if you want to look the the CLF data, 3d polars etc
https://www.danleysoundlabs.com/support/clf-files/
Best
Tom