These are great speakers.
I did a review of them a bit over a year ago. Easily the best AMT tweeter I have ever heard. These made me believe AMTs could be really good.
As you are already aware, I am using AM Ribbon tweeters in my HT system on all seven of them. They are the Airborne RT-4001 models. Both Meniscus Audio and Solen.ca sell those wonderful tweeters which are available for only $60.
Here are the frequency response curves for that driver which can compete with some costing multiples of their asking price:
Photo 1 is that supplied by Airborne
Photo 2 showing what was measured in my living room using the Dayton Omni MIC Speaker Testing device. A rather smooth frequency response from 2 to 20 kHz.
NOTE: Filter frequency between midrange and tweeter drivers is set at 3500 Hz.
Photo 3 is the left portion (LF section of the chart above and the corresponding SPL)