Air Motion Transformers. Technically not ribbons at all.
You should absolutely not buy based on a label like AMT or Be or anything else. Having said that, the best AMT’s are as good as the best in the world. There are also mediocre AMT’s, like mediocre diamond and Be tweeters that are just not stellar.
I use Mundorf AMTs in my custom speakers, but Beyma also has fans, as does the original brand, ESS.
At their best (and I exclude GE speakers because I’ve heard them), AMTs vanish. They just aren’t there. They have incredible dynamic range and low distortion, which I have measured. This isn’t hype. The variety in sizes provides not only lower extension but controlled dispersion, something I like as an apartment dweller, and a big advantage over dome and ring tweeters if that’s’ your need.
Like the very best Be and Ribbon tweeters, AMTs are practically zero mass and have almost zero energy storage. They don’t ring at all. This gives them an incredible transparency.
But I repeat, there is a very wide range of quality. Alone, AMTs is not better than anything else, but at the top of the range, they’ll compete with anything.
Best,
E