Advantages of beryllium?

Don't be fooled just by the Be brand. They are not all equivalent, certainly not in frequency response or dynamic range.

In _theory_, be is very stiff and very light, so least stored energy or resonances of most materials.

The implementation of the suspension, motor, and overall speaker design is VERY important. Done well the best Be tweeters are among the best tweeters. But so are the best AMT's and ring radiators too!

Best,

E

One good eye opener, listen to the Magico Be tweeters and compare to the Focal's.

Personally I find the tuning of the Magico's a bit bright, but butter smooth and wide dispersion spanks all the Focal's and certainly the B&W diamond tweets.

It's all in that luscious motor assembly that's behind it.

Best,

E

Highly rigid and light but poor internal damping.

Personally I don’t like the splashy sound of drivers of this type design (metal and highly rigid). They have great bandwidth that makes for impressive measured performance but I find the sound is "splashy" due to the way rigid materials vibrate naturally (like a bell vibrates and rings after an initial hit but a damped material like a pillow does not).

Splashy is a good term - as in when you splash the water it makes a lot of sound after the initial splash. Acoustically this means the driver imparts its own sound to the timbre whereas an internally damped cone material is much more inert - contributing much less coloration after the sound stops.

I prefer damped designs even though they tend to have a narrower bandwidth and can suffer from breakup and therefore require more careful design and larger more expensive drive motors. Damped cones sound much more natural and faithful to the original tone/timbre of recorded instruments even if they are not as linear on a speaker frequency plot.

Here is an example of a titanium tweeter - look at the ringing in the waterfall plot in the treble !!!

https://www.stereophile.com/content/jmlab-utopia-loudspeaker-measurements-part-2

Here is an example of Be - similar problem in the treble but very much better than titanium

https://www.stereophile.com/content/focal-maestro-utopia-iii-loudspeaker-measurements

beryllium is 1/3 lighter than aluminum yet 6x the specific stiffness of steel

IIRC, it outclasses Ti in that way - dunno re stress cracking but the newest Ti alloys are better than their reputation

the dust is highly toxic - ask Porsche who used them - briefly - on brake components of some race cars

might be fun to see if the German govt. allows Be in speakers - you can get away with putting toxic liquids in cables in Canada and importing them into the US though