The Whole Truth About Beryllium Diaphragms

[mowry]

After a year of research I uncovered and compiled an interesting story from within the loudspeaker industry. You can download my manuscript here, http://www.s-m-audio.com/truth.zip Feel free to distribute this file.

[BHTX]

Using AbiWord, Wordpad, etc.. none of the images are working, causing a lot of errors. Do they need to be included in the zip?

[mowry]

The file was written with MS WORD 2000 SP-3.

Can you try Open OFFICE?
http://download.openoffice.org/index.html

[BHTX]

Yeah, I was hoping this wasn't the case, but I'm not surprised. Compatibility between office suites and word processing apps etc has always been an existing problem. I used to use Open Office, but always had problems with it. I've had MS Office 2003 (and all the rest before it) as well, and couldn't stand it. Truth is, I just need to build another PC, as this one is just getting too old.

Anyway, after messing with the errors and objects blocking the text, preventing me from being able to see it, I did finally manage to read the entire article.

Nice job, to say the least. These kinds of things do make me a bit furious. Congrats on all the work.

[critofur]

Thank you for the work of putting that together and sharing it.

I was able to view the file properly using the free Open Office.

Did you have any commercial motivation to put that document together?

I had been wanting to buy some 2 - 3" Beryllium domes back around 2002 - 2003, but the price seemed unreasonably high and Brush Wellman seemed to be the only source I couild find for authentic Beryllium products.

[augerpro]

Good stuff and I've followed the investigation you did back with the TangBand tweeter.

Couple observations. The Usher situation isn't clear in my mind, because although they admitted using SONIC, their domes are not the copper color that SONIC's 98% Cu domes are. So what are they? And why would Tsai mention the anodizing/oxidation process if nothing like that is remotely involved, by anyone making these diaphragms?

As for Sonance their literature does seem deceptive. But that doesn't mean that composite or sandwitched diaphragms using Be may not be good. Depends on what you are trying to accomplish. How does inherent damping play into this for example? Where is the tradeoff between super rigid but low damping, and less rigid but high damping? From this POV and your own focusing on Speed of sound versus density, the Accuton alumina diaphragms look quite superior. Push the break up farther up AND damp it. Pretty clever, gives me a new respect for Accuton. Given that where does the Be ceramics fit into this? Maybe similar to the Accuton performance, but even higher breakup? Now that would be a woofer I would buy!

Which brings me to my last point. Many factors make a driver superior, why all the geekiness of speed of sound in a material? I've seen measurements of both the Usher Be tweeter and its Al version (Dayton RS28). The frequency response and distortion are identical. The different materials don't seem to have much effect. The common Al/Mg domes don't break up until well past 20khz, some past 30khz. Who cares if you can push this out even farther?

Hope none of this comes off as refuting what you are saying. Clearly some people are playing off the markets desire for "hgih tech", I just wanted to bring different perspective that looks at why Be is desirable in the first place. You kind of start to sound shilly at the end for Brush Wellman. I've followed your work, so it doesn't bother me too much, lab results are what matter anyway, but just saying...

[bear]

Gee! Steve!

Nice to find you on here!
I've been reading your stuff for years now... great reading!

Nice insights into the whole industry... and this article as well.
How do you speel it? Bearealium??

Regards,

_-_-bear

[mowry]

Guys,

Why not write to these folks at Usher Audio and ask them what's up?

usher@ms11.hinet.net
info@musikmatters.com
audioltd@metrocast.net

Then you can better understand why they call em Dancers.

[soongsc]

I think rather focus one the material, it's better to focus on final driver performance. I never believe in all this material magic stuff. I enjoyed the reading though. There are lot's of stories behind daimond diaphragms as well. The fact is, as long as you have a strong breakup mode below 50KHz, you are most likely going to have harsh sound.

[dantheman]

Thanks Mowry! Hard work much appreciated.