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.

[DcibeL]

I think most people who buy Be or diamond diaphragm speakers are paying a huge price premium just so they can tell their friends that they have some very exotic Be or diamond speaker. It's too bad there have been some false claims made by manufacturers to make a few bucks because people do buy into Be just because it's Be.

Originally posted by soongsc
The fact is, as long as you have a strong breakup mode below 50KHz, you are most likely going to have harsh sound.

Fact? Soongsc, can you point me to some measurements or some data that could help prove your point? How can aluminum 1" tweeter with breakup at 25-30kHz have harsh sound? We don't hear the breakup, and for any harmonic distortion that propagates lower in frequency, the harmonic occurs at the breakup frequency which is above audible range. I don't see why the breakup must be above 50kHz, for me as long as it is above audible range there is no problem.

[rdf]

Originally posted by mowry
The file was written with MS WORD 2000 SP-3.

While OpenOffice has it built in, you might consider a PDF print driver such as CutePDF. The resultant file is (for most) read-only and also significantly smaller than DOC. Thx for the article too.

[gedlee]

Hey Steve

I read your paper, but it was not immediately apparent what the point was. That people in audio streeeeeetch the truth to the point of lies? Whats new about that?

[DcibeL]

Originally posted by gedlee
I read your paper, but it was not immediately apparent what the point was. That people in audio streeeeeetch the truth to the point of lies? Whats new about that?

Moreover, Steve worked for Bose, so he should know all about that!

I kid...

[mowry]

Originally posted by gedlee
Hey Steve

I read your paper, but it was not immediately apparent what the point was. That people in audio streeeeeetch the truth to the point of lies? Whats new about that?

Earl,

Well that's part of my point. Mike Klasco wrote about this problem in 2004. At that time, the analysis revealed zero berillium. In 2007, new analysis indicated 6075 mg/kg or 6075 parts per million. No matter how one dances with that, it's still Bogusium today.

[augerpro]

Originally posted by mowry
Guys,

Why not write to these folks at Usher Audio and ask them what's up?
Then you can better understand why they call em Dancers.

Why ask them if they aren't credible so far? I'm asking YOU what diaphragm you think they were using that is grey, yet sourced from SONIC, which uses 98% copper and is copper colored? I'm genuinely interested.

[mowry]

Here's the SONIC material test report, 6075 mg/kg or ppm Be or 0.6075% Be by mass. Titanium is 88.47%.

www.s-m-audio.com/grayfoil.pdf

[DcibeL]

While the company may have mislead us by stating the material is Be, Titanium can surely still make for a good diaphragm.

I remember saying this in another thread, may have even been a thread about Be, but it is not so much the material of the diaphragm that makes one speaker better than another, but how that material is implemented into the design. The result of all the components of a loudspeaker dictates it's performance. That said, paper cones are made of a hundred different things, and we are lucky to be told that it is anything other than "paper" by the manufacturer. I think we should be happy that the manufacturer's tell us anything about the materials used. We seem to be perfectly fine with knowing that a diaphragm is "paper", should we not be equally as happy to know that a diaphragm is "metal"?

[augerpro]

Originally posted by mowry
Here's the SONIC material test report, 6075 mg/kg or ppm Be or 0.6075% Be by mass. Titanium is 88.47%.

www.s-m-audio.com/grayfoil.pdf

Haha that's terrible. I suppose they figured the copper color was a dead giveaway so use Ti to get that gray color.

[ZilchLab]

Originally posted by DcibeL
I think we should be happy that the manufacturer's tell us anything about the materials used. We seem to be perfectly fine with knowing that a diaphragm is "paper", should we not be equally as happy to know that a diaphragm is "metal"?

I believe it's called "Fraud."

p.s.: I'll not be coming to your restaurant, ordering the Filet Mignon, and be satisfied with you serving meat and meat byproducts instead, even though dog food may be equally nutritious....

[gtforme00]

Fair enough, but what if the cone were 98% paper and 2% kevlar, and the manufacturer told you it was "Kevlar".

Even though Mr. Mowry has an interest to protect, I am glad that he is exposing this issue for what it is. If the end product is better loudspeakers for us to play with, then I am grateful.

Have you looked at the STEALLUS motor design, it's quite remarkable, I wonder when a driver based on it will be available.

-David

[soongsc]

Originally posted by DcibeL
I think most people who buy Be or diamond diaphragm speakers are paying a huge price premium just so they can tell their friends that they have some very exotic Be or diamond speaker. It's too bad there have been some false claims made by manufacturers to make a few bucks because people do buy into Be just because it's Be.



Fact? Soongsc, can you point me to some measurements or some data that could help prove your point? How can aluminum 1" tweeter with breakup at 25-30kHz have harsh sound? We don't hear the breakup, and for any harmonic distortion that propagates lower in frequency, the harmonic occurs at the breakup frequency which is above audible range. I don't see why the breakup must be above 50kHz, for me as long as it is above audible range there is no problem.

If you ever drop by Taiwan, I'd be glad to entertain you with the details. But you have to be here to hear it. I have already demonstrated to a few people here.

[mowry]

What's the difference between a 28mm Aluminum Dome Tweeter and a 28mm Truextent Acoustic Grade Be Dome Tweeter to the driver manufacturer?

About US$30.00 per Tweeter unless the assembly builds poorly and the reject rates are high.

[panomaniac]

Steve, I sent you your doc in PDF format a couple of days ago. Thought you might like to post it. Did you ever get it? Easier and smaller than the zipped docx file.

Thanks for the post and the info!

[Ron E]

Originally posted by 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.

I've never had an issue with compatibility between Open Office and Excel, except when the Excel doc included VBA code. If you want to keep folks with open office from mucking about with your spreadsheet, put in some VBA, It's a feature, not a bug

I use open office almost exclusively, but have an old version of excel for times when open office doesn't cut it - mostly this is when open office's charting problems rear their ugly head.....