I am a huge fan of Yamaha NS-1000M's and IMO, the Beryllium mids and tweeters are what makes the soundstage and imaging so memorable. Interestingly, Be drivers are still used in Paradigm Reference speakers and Usher Dancer series, both of which I would like to hear. Here is some info on Be drivers:

http://www.berylliumproducts.com/Acoustics.aspx

One of the biggest and more expensive speakers made in Europe, Focal.JMlab Grande Utopia Be, uses beryllium too.

The Focal Grand Utopia Be is 450 pounds each!

Yeah. And, they cost around $90,000.

Sure they're expensive, but I'll bet they sound really good.

ADS used beryllium mids and tweets in their magnificent L1530.

Most ADS I seen and heard use rather cheap looking drivers so if in fact they used Be in the L1530, that would be a surprise. I Did a web search on the L1530 and couldn't confirm the domes are Be. Do you have more info?

my mistake, they used samarium cobalt on the tweeter only, not beryllium (dang those confusing exotic metals), per the L1530 owners manual courtesy of Duffinators ADS Speaker Reference pages @ http://sportsbil.com/ads/.

also posted in the Brochure here at ST http://www.sound-thinking.org/index.php?sh...indpost&p=31832

Here is a pic of the L-1530 from my local CL. BTW, for sale at $300. NOT MINE!

if they are in good operational condition thats a steal.

The pioneer DSS-E6, DSS-7, and DSS-9/E10's have boron cone midranges and horn loaded beryllium ribbon tweeters. They use TAD drivers, and TAD uses beryllium a lot.

Boron is element number 5 on the periodic table, it's pretty nice for sound transfer applications too!

Ribbon tweeters are my personal favorite


The Pioneer S-910 and S-1010 also have beryllium ribbons.