Again, I've looked-for years-and only found two diyers who did but stopped do so long ago. That said, and not being a diyer, I simply can't risk going there.
That's obviously quite true. But it's unfortunate and frankly kind of suspicious why this seems to be the only polar I could find of any JMLC horn, and it being a 1" throat and/or 800Hz Fc, as you pointed out, it won't perform as well (more distortion?) as the AH425. https://josephcrowe.com/products/horn-no-1689-1khz-es-circular-horn
https://cdn.shopify.com/s/files/1/0...22-95c7-7e762c1568f5_480x480.png?v=1656104000
https://cdn.shopify.com/s/files/1/0...22-95c7-7e762c1568f5_480x480.png?v=1656104000
However, comparing the above polar charts is hardly useful given the difference in the drivers.
https://www.rcf.it/en/products/product-detail/nd950-2.0
https://www.rcf.it/en/products/product-detail/nd350
Given the above facts, and as I've only had opportunity to hear Troy's ES450 horn, that should be the horn to compare with the sound of the TH4001. A real shame that I can't make the trip to hear Pierre's Radian 745Be/4001 combo. Otherwise, if I loved what I heard I'd get a pair of 2" throat 3" diameter Radian 760Be; no adapters needed.
That's an option for this horn
https://josephcrowe.com/products/es-600-bi-radial-wood-horn-no-1978
A polar measured with an unknown driver.
https://cdn.shopify.com/s/files/1/0142/2848/8292/files/polar902_480x480.jpg?v=1602552211
Don't know if that's also true of the ES450
https://josephcrowe.com/products/3d-cad-plans-for-es-290-biradial-horn-horn-no-1670 and the much bigger and much more costly ES290. https://josephcrowe.com/products/es-290-biradial-wood-horn?variant=41821876682836
However, Troy also says "If we are having a general discussion about ultimate sound quality, then it needs to be pointed that a larger horn will provide a larger sense of scale and clarity, and in turn a more engaging listening experience. If we talking cost-no-object ultimate sound quality then the ES-450 or ES-290 Biradial.....will provide those attributes mentioned."
https://josephcrowe.com/blogs/news/...river-test-review?_pos=3&_sid=8fc338e04&_ss=r
Would "greater sense of scale" likely be more true of the ES290 because it appears to have a substantially lower directivity pattern than the ES450, albiet measured using different midrange drivers.
https://cdn.shopify.com/s/files/1/0...BMS_4591-8_off-axis3_480x480.png?v=1649504045
https://cdn.shopify.com/s/files/1/0..._Filled_Contour_Plot_480x480.png?v=1697218866
Thus, the ES290 may create more indirect sound (more secondary reflections?), and thereby generate a more spacious sound than the narrower ES450.
But I'm wondering if a true constant directivity horn may be a better choice-and if so choose that as an option for second speaker build. Like one of the JBL CD horns those here have mentioned. Or the TH4001, which at least in the horizontal plane is basically CD. Or does might that horn have some issues? https://audiohorn.net/img/bi-radial/TAD-TH4001-polar.jpg
If you prefer the sound of more reflections, adding more of your room's sonic character to what you hear, then wider coverage would be the obvious choice.
A dodecahedron speaker is near the ultimate for creating more indirect sound.
Since you still wonder what choice to make, choosing to compare multiple choices in your home environment makes sense.
Every horn, driver, and room has "issues", each listener perceives those individual characteristics differently.
Fortunately, there are no shortage of options to satisfy each individual's fluidly changing preferences.
Art
Perhaps as Pierre and others might have found the AH425 horns, the DS3's directivity pattern would be at the opposite extreme, as an apparently experienced listener discovered; post # 58.
https://www.audiosciencereview.com/...est-design-available.19024/page-3#post-623930 Unlikely an attractive option and little chance of hearing it any time soon.
It has a LOT of cancellations at higher frequencies, the norm for spherical radiation doesn't go to very high frequencies.
But with enough distance and when you want diffuse surround speakers or something similar ... in times of 3D printing this is closer in reach as ever.