Beryllium Tweeters

Given it appears in various sources that Materion (the sole supplier) is going to be discontinuing the manufacture of beryllium foil that is used in tweeters, is there any insight as to what will be replacing that material? Carbon fiber? Silk? 

Apologies if this is too off point.

Hi, first post here.

We do offer the BlieSMa 25 mm and 34 mm beryllium tweeters on our Sun Audio Purified 4 modular loudspeakers. Air and sweetness are superb. However, if you are looking for extension/wide dispersion, the T25A has a horizontal directivity of 160° up to almost 15kHz, and only -2dB @20kHz and 60°. 

HiFiCompass has published a comprehensive review of the BlieSMa tweeters.

Good AMT and ring radiators may sound good to you, but i find a lot of Be tweeters to be splashy and over saturated with color, so compared to that you may find a lot of designs to be underwhelming.