Just look at my first measurement. Bliesmas Beryllium membrane works as piston far over 30kHz, membrane resonance at about 50kHz! (The dip at 38kHz is from the protection grill. Without it goes linear till the resonance). My experience with this tweeter is a detailed reproduction mut without metal "shimmer/pronaunciation" at higher frequencies.
Normal metal tweeters have their resonance in the 20-30kHz are. We are not able to hear the resonance but (especially the old Seas tweeters with the resonance around 20kHz) I never liked the sound of them - the less the closer the resonance is to the hearable spectrum.
So Beryllium has definitely an advantage I can not get with other materials for my use - so I have to take it.
(I have to build a reference speaker for measurements with extended frequency range to 60kHz/94dBSpl and up to 100kHz at lower level. This is not possible with most tweeters. The measurements of the "diamond" membran I found >20kHz don't show a good result for this use, so I never tested them)
If one is trying to do this repair at home.
Learn from car repair shops, how do they fix less severe dents ?
By not touching it in any way, apply a suction cup, and pull it straight back out. Often the result is good enough that it does not need more attention.
A 'suction cup" of suitable strength and physical size, is the method that has the most chance of success, on foil diaphragms.
Probably difficult to find in an appropriate size.
Other methods will not give a satisfactory end result.
Learn from car repair shops, how do they fix less severe dents ?
By not touching it in any way, apply a suction cup, and pull it straight back out. Often the result is good enough that it does not need more attention.
A 'suction cup" of suitable strength and physical size, is the method that has the most chance of success, on foil diaphragms.
Probably difficult to find in an appropriate size.
Other methods will not give a satisfactory end result.