Advantages of beryllium?


Can someone please explain the advantages of beryllium drivers over titanium or aluminum?

Also, how concerning are health risks associated with beryllium?

many thanks for your input. 
defiantboomerang
@randy-11

Interesting link. I think they sum it up very well. Be is better in the very top octave than Aluminium or Titanium (10 to 20 KHz)

Note that on the plots Be is not necessarily the best from 3 to 10KHz (the really important range musically for the tweeter). This is the point I am trying to make about internally damped drivers - better performance over a narrower frequency range. If the sound from 10KHz to 20KHz is most important to you then Be is the way to go (at the expense of more resonance at 3KHz to 10KHz)

As as far as I am concerned there is not so much musically in the 10K to 20KHz range - so I prefer a tweeter that performs better from 3KHz to 10 KHz.
A - The 936 is not very clean
B - It has the Focal 100 Hz dip in impedance, which makes the speakers seem more "discerning" of various amplifiers. In some cases this is done artificially in the crossover.

Best,

E
shadorne, I dunno if what they say is accurate but it does seem to be a  pretty good summary - I'm not a dome kinda guy (Maggies) - tho if someone offered me a free pair of Sonus Faber Aida's I could be persuaded to switch.
@erik_squires 

Does the 936 have a Beryllium driver? Or is that reserved for higher up Focals?
Per the web site, it is Al/Mg.

Nothing against Al/Mg but Focal has this fetish for micro motors which are never as smooth or dynamic as the large motor variants.

Though lately ScanSpeak has produced some tweets which are close to the same motor size and very very good sounding.