The best tweeter design

As far as ribbons being beamy. In my experience, not all ribbons are beamy. It does have more to do with ribbon design (dispersion pattern) but not all ribbons are beamy. Also, some of this can be overcome, by crossover frequency & slopes. I've seen open back and sealed back ribbons and one where the ribbon was mounted horizontally. Hopefully everyone has sat in front of a good set of ribbons, what they do, they do very well. Again, I've always been a budget builder. I've tried a few sets of HiVi's, theirs are a mixed bag and some of their ribbons have an extensive rise on the high end that bothers me, One in particular was quite good. I've played with Bolender Graebner and an old Fostex. Some of the Fountek look promising and I've seen great results with RAAL. Unfortunately, I have not yet figured out how to just look at a ribbon and tell if it will be beamy. I know none of this is really a help, but to say, there is alot out there, some of it is very good.

Why is an inverted (concave) dome on this list if a conventional (convex) dome is not unless made of diamond or horn-loaded, and leaving out 'soft' domes unless configured as a "ring radiator"? Too arbitrary to be meaningful IMO.

[I'm deleting the rest that originally followed the above and reposting it in a new thread.]

I'll take the Lansche plasma tweeters. Zero mass, no ozone production (as it is converted into pure Oxygen). The sound is incredible.

a tweeter is only as good as the capacitor in front of it! a few years ago I have change the stock mundorf silver/gold caps in my avantgarde omega duos against teflon v-caps. the improvement was dramatic. a costly upgrade though.
really amazing how much music "gets lost" in even a good mundorf cap!!

duomike :

a tweeter is only as good as the capacitor in front of it!

I guarantee that if I were to swap your capacitors out and put in generic poly film capacitors you would not hear a difference - it is the knowing that changes your perception rather than the actual sound changing.

My friend did this experiment, a customer sent fancy "gold" capacitors to be used in multiple sets of speakers - he used those as requested except one pair of speakers was made with generic film capacitors.  If he could compare the speakers and hear which ones didn't have the gold capacitors he could have another pair of the speakers free, and the one set of gold capacitors would be installed in the next order regardless - the customer replied : don't bother using the gold capacitors anymore, there is no discernible difference no matter how try I hard to hear it (because he didn't know which one had the "regular" caps, and there was no actual difference in sound, he could not detect by listening).