Beryllium Tweets

"Breakup distortion" is exactly the point here.  Soft dome tweeters are great and forgiving, but they are not quite as clean and transparent as hard dome tweeters.  The problem with hard dome / metal dome is the breakup distortion (the point where the material flexes and distorts from the movement).  The breakup point of normal metal domes can range anywhere from 19 khz to 28 khz (on some of the best / treated / coated tweeters).  However, they will still have a bit of a bright edge.

Alternative materials have shown a much higher breakup frequency because the material is stiffer.  I think beryllium is somewhere around 45 khz or something.  Diamond is upwards around 75-80 khz.  I think ceramic is higher in these areas as well, but ceramic also presents a more controlled sound that is usually not as dynamic.

In a recent speaker project, I went from a Seas Excel softdome ($322) to a Seas Excel Berillyum ($770).  The change was night and day. The Beryllium was much cleaner and much more realistic with a higher resolution.  No harshness at all!

@kijanki I wonder where the new Yamaha NS5000 driver material fits into that list. Yamaha was the first to use  Berylliumin in the 1970's. They are saying that their new material is better than  Beryllium.

In a recent speaker project, I went from a Seas Excel softdome ($322) to a Seas Excel Berillyum ($770). The change was night and day. The Beryllium was much cleaner and much more realistic with a higher resolution. No harshness at all!



hummm now ya got me reconsidering,,,after having read a  bit of~~~insider opinion~upon mentioning my great appreciation for the SEAS Thor, especially the Legendary Millenium,,,said the rep, he perfers the Millennium vs the Beryllium. 
back when my set up had the Jadis Orch Refer with EIKT90 ~~although they voiced a  harshness in upper range, their voicing in human vocals was outsanding **soundstage**. Employed Amperex Bugle Boys in the 3 pre slots,,as i was unaware of Telefunken's superior range at that time in my audiophile journey. Shoulda kept the JOR and moded it out with all new caps, new power 6550's (Svetlana vs Shugaung??) and employed the Telefunken,,I'd be alot further ahead and  more cash in my back acct.
searched all over YT for the Beryllium tweet experience, nothing, much, just a few low level muisc vids which made it impossible to determine the voicing of the Be.
So just maybe , after I pay for my mod today of swapping out the new carbon Film resistors for Takman metal resistors (which jadis had employed originally in the Defy),,,just might give the Beryllium tweets a  try, ,,there is a pair offered on ebay for $220,,from china,,so can not return. It is hard for me to imagine any tweet which can voice as the Millenium under optimum  components. 
For me the Millennium is the benchmark for all tweeters. 
But for $220, i'm willing to take the chance. 
Can not afford to experiment with the Seas Beryllium,,as it is wayyy out my budget. 
After I pick up my Defy today,,I will upload a  new YT vid with another cam which has a  external mic,,as the Sony only offers builtin mic and offers poor sound resolution.
Will post a  YT vid here, tonight,,,My hunch is the Takman metal (plate)resistors are superior to the carbon film.
Jadis employed Takman in the design for a  good reason. 

I have them in my MAGICOS they sound wonderful you are entitled to your opinion(which is WRONG).

The motor in the Magico's far outclasses the micro-motor tweets in Focals.

It is only because of marketers that we even think of Be as a selling point. 
Don't get me wrong, Be is a cool high tech material, but a specific Be tweeter is a very different thing than the brand that Be has become.