Berylium dome tweeter

[kelticwizard]

With tweeters, I see adversments like aluminum dome, titanium dome, cermaic dome, silk dome, diamond dome, etc. If you look at the real contents, each have a different percentage of the material advertised, each have a different material structure.

Aluminum domes are not really made of aluminum, ceramic domes are not made of ceramic? Can you give examples?

Unless you mean that the cloth of the dome is coated with aluminum or ceramic, so it is actually an aluminum/cloth dome and a ceramic/cloth dome. But since the cloth functions as the surround it is difficult to imagine any other construction, or what practical advantages such an alternate construction could bring.

Is this the point you are making? If so, I don't think many will find it very compelling.

The same thing in common is that they specify what the manufacturer considers the material most significant for it's performance. I think that we should accept this. The final performance is what we are looking for.

I repectfully disagree. There are certain materials in products which increase it's value merely by being genuine. If I sell people an oak chest, the buyer has the right to expect it to be built of oak. If it turns out that only the top of the chest is oak and the rest is laminated pine or MDF, would that pass your standard? After all, the pine/MDF chest will hold your socks and undershirts just as well as the oak chest will.

I would think that any organization which purports to uphold standards and allows a manufacturer to pass off an "oak chest" with oak on the top and pine/mdf throughout the rest is not really performing it's function, don't you agree?

If we start looking at all commercials, there are just too many examples that can be considered misleading. So I just think we as consumers should either face the facts, be smart, or use our influence to change the laws/regulations....

There are over 190 countries in the world. Do you want 190 separate commercial codes with no relation to each other? How will international commerce be possible?

That is why international organizations which uphold standards are so important. These help separate countries "get on the same page" so to speak, so eveyone knows that products meet certain standards and their claims are genuine. But in order to perform this function, these organizations must maintain these standards in the products they pass. Allowing a manufacturer to call an alloy of 98% copper and 2% beryllium a "beryllium alloy", especially when there are manufacturers who go through some real expense to make competing products out of pure beryllium, is hardly setting a good example. Unless there exists some recognized convention that an alloy of 2% Metal A and 98% Metal B is referred to as an "alloy of Metal A", which does not appear to be the case.

 

[DcibeL]

10 karat gold is 42% gold-just a smidgen below half. Glancing at gold related websites, I see that 10 karats is the lowest percentage the gold industry seems to be concerned with-no mention of 6 karat gold or 2 karat gold.This pretty much indicates that the gold industry has recognized that once a substance gets even a little below 50% gold, it really does not exhibit enough gold-like properties to be referred to as gold. The fact that they make the dividing line 42% instead of 50% is not that important-an alloy has to have near 50% of a metal to be called that metal, even in a generic sense.

Here we are dealing with a company which calls an alloy of 2% beryllium, at least 90% copper and up to 8% other metals a "beryllium alloy". It is obvious this thing does not have enough beryllium in it to exhibit any appreciable amount of beryllium like properties.

That's not the point I was trying to make. I feel that you are arguing just for the sake of arguing here.

 

[soongsc]

Aluminum domes are not really made of aluminum, ceramic domes are not made of ceramic? Can you give examples?

Unless you mean that the cloth of the dome is coated with aluminum or ceramic, so it is actually an aluminum/cloth dome and a ceramic/cloth dome. But since the cloth functions as the surround it is difficult to imagine any other construction, or what practical advantages such an alternate construction could bring.

Is this the point you are making? If so, I don't think many will find it very compelling.





I repectfully disagree. There are certain materials in products which increase it's value merely by being genuine. If I sell people an oak chest, the buyer has the right to expect it to be built of oak. If it turns out that only the top of the chest is oak and the rest is laminated pine or MDF, would that pass your standard? After all, the pine/MDF chest will hold your socks and undershirts just as well as the oak chest will.

I would think that any organization which purports to uphold standards and allows a manufacturer to pass off an "oak chest" with oak on the top and pine/mdf throughout the rest is not really performing it's function, don't you agree?



There are over 190 countries in the world. Do you want 190 separate commercial codes with no relation to each other? How will international commerce be possible?

That is why international organizations which uphold standards are so important. These help separate countries "get on the same page" so to speak, so eveyone knows that products meet certain standards and their claims are genuine. But in order to perform this function, these organizations must maintain these standards in the products they pass. Allowing a manufacturer to call an alloy of 98% copper and 2% beryllium a "beryllium alloy", especially when there are manufacturers who go through some real expense to make competing products out of pure beryllium, is hardly setting a good example. Unless there exists some recognized convention that an alloy of 2% Metal A and 98% Metal B is referred to as an "alloy of Metal A", which does not appear to be the case.

If you wish for me to provide my view on specific commercial adds, you may post it. But I don't think any commercial add is impropriate. I just think consumers don't ask enough about a product. There is not company that will openly publish a specification that will meet the needs of each and every person purchasing anything. The consumer just have to ask.

Talking about wood, heh, I really don't want to comment because that's about as diversified as audio equipment. Even with oak, grown in different places, the properties and durability are different. Different parts of the oak has different properties as well. Again, the consumer just has to ask and learn more about it. Some consumers care and some don't.

Beef, how do you specify it to really be sure the consumer get what they want? Show me a spec for beef, and I will ask you lots of questions and tell you how insufficient it is.

Talking about the beryllium versus alloy, anyone can tell by the color that it is not pure, it's really a no brainer, I didn't think it necessary to do any tests unless you really want to know how much beryllium is in there, and there was no intent to make it look like pure beryllium, so I really don't see anything wrong with that. It's like when someone sell you a gold watch, just one look and you know it cant' be pure gold.

If you think the international organization will regulate everything. If they did, why the "mad cow" issues? Is the regulation too generic? If so, shouldn't the international organizations do something? The real difficulty is still communication, education differences, and trust among the countries. Sad thing is that developed countries don't trust undeveloped countries because of educational differences, and vice versa. If international organizations really want to solve the problem, they should start with education systems. Lot's of advanced countries take the position "if it's good enough for me, it's good enough for you", but if the undeveloped countries take the same position, then the idea get's thrown out the window.

 

[mowry]

There are other considerations that should be considered. For example common 304 Stainless Steel has superior mechanical properties to CuBe2.

Density:
CuBe2 8250 kg/m^3 304 SS 8000 kg/m^3

Modulus:
CuBe2 125 x 10^9 Pa 200 x 10^9 Pa

Poisson's ratio:
CuBe2 0.30 304 SS 0.29

Speed of Sound:
CuBe2 4000 m/s 304 SS 5000 m/s

The reasons for not using 304 SS for a transducer diaphragm are obvious. So why use CuBe2? Could it be fundamentally related to intent to deceive?

There are other companies that are even more flagrant in their quests, SONIC (http://www.yingpo.com/english/index.htm) for example. Their Beryllium is 88.47% Titanium and 0.6075% Beryllium (http://www.badongo.com/file/12388488), yet they represent their domes and cones as "Beryllium". They even give them a coat of paint to match the color of Acoustic Grade Be, 98% or better (http://www.electrofusionproducts.com/web/bpdweb.nsf/AllDocsByID/A056E254C789C3DA88256E160024517E/$File/China_Be_Domes_Report.pdf). Here's a picture of Fake Be on the left, the cone and Real Be on the right, the dome, http://www.badongo.com/pic/4833197. The cone has a density of ~3750 kg/m^3. Titanium has a density of ~4000 kg/m^3.

Are companies using SONIC's domes and cones and representing and advertising them as "Beryllium"? Oh yes some that are considered "High-End" and my investigations are ongoing.

You can help. I have been able to locate only one source of Beryllium foil and/or formed beryllium domes. Beware, I cannot identify any source for cones except TAD (Pioneer) but they are used in the TAD Reference Series only. Can anyone identify any supplier(s) of beryllium foil? Can anyone identify any other companies that misrepresent their speakers as "Beryllium Tweeters et al."?

Kind regards,

Steve

http://www.s-m-audio.com/steve_mowry.html

 

[soongsc]

Thanks for the info mowry, I'll check it out. But only the SONIC link works. Are you trying to say that SONIC Beryllium cones/domes are not really Beryllium even though they look like it?

I know that Beryllium cones are so brittle that they have problems as cones in many low requency applications. Could be some form of Beryllium alloy is necessary to solve the problem.

By the way, is mowry also a brand name?

 

[mowry]

Thanks for the info mowry, I'll check it out. But only the SONIC link works. Are you trying to say that SONIC Beryllium cones/domes are not really Beryllium even though they look like it?

I know that Beryllium cones are so brittle that they have problems as cones in many low requency applications. Could be some form of Beryllium alloy is necessary to solve the problem.

By the way, is mowry also a brand name?

soongsc

Yes, Sonic beryllium cones and domes are 0.6075% beryllium and 88.47% titanium. The link to the test report by SGS is here http://www.badongo.com/file/12388488. The link is good but slow. You must also enter a download code that is given on the right hand side of the download window once it fully loads. If you cannot download, send a message here steve@s-m-audio.com and I will send it attached to return message. Here's another report on domes from SONIC, "http://www.electrofusionproducts.com/web/bpdweb.nsf/AllDocsByID/A056E254C789C3DA88256E160024517E/$File/China_Be_Domes_Report.pdf". You may have to copy and paste the link into your browser's window but the link is good.

Only one company has real beryllium cones and that's TAD (pioneer). There have been no reported problems with these cones. At least I cannot find anything when I search. They are used in the TAD Reference Series only. The Ceramics such as Aluminum Oxide cones from Accuton for example are more brittle than beryllium and there have been reports of cracking and breaking.

Mowry to the best of my knowledge is not a brand name for anything. Where did that come from?

Not here "http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=DVXA,DVXA:2005-08,DVXA:en&q=mowry"

 

[Robh3606]

"I know that Beryllium cones are so brittle that they have problems as cones in many low requency applications. Could be some form of Beryllium alloy is necessary to solve the problem."

It depends on how they are manufactered. The JBL and I believe the Focals are from Be Foil and are much more forgiving than the original TAD diaphrams which were electrodeposited on copper and then the copper was etched leaving the Be. I actualy have a damaged JBL Be foil diaphram and it doesn't shatter. It acts just like a damaged aluminum of Ti diaphram. As far as I know these guys are it. The tested Dome report is the first link on the page.

Rob


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

 

[Cal Weldon]

Funny how our language works isn't it?

If you start with copper and add beryllium (less than 50%) it's beryllium copper.

If you start with copper and add beryllium (less that 50%) it's copper alloy.

So I vote for beryllium copper not beryllium alloy.

Give 'em another call. I'm sure they'd be glad to hear from you.

 

[soongsc]

soongsc

Yes, Sonic beryllium cones and domes are 0.6075% beryllium and 88.47% titanium. The link to the test report by SGS is here http://www.badongo.com/file/12388488. The link is good but slow. You must also enter a download code that is given on the right hand side of the download window once it fully loads. If you cannot download, send a message here steve@s-m-audio.com and I will send it attached to return message. Here's another report on domes from SONIC, "http://www.electrofusionproducts.com/web/bpdweb.nsf/AllDocsByID/A056E254C789C3DA88256E160024517E/$File/China_Be_Domes_Report.pdf". You may have to copy and paste the link into your browser's window but the link is good.

Only one company has real beryllium cones and that's TAD (pioneer). There have been no reported problems with these cones. At least I cannot find anything when I search. They are used in the TAD Reference Series only. The Ceramics such as Aluminum Oxide cones from Accuton for example are more brittle than beryllium and there have been reports of cracking and breaking.

Mowry to the best of my knowledge is not a brand name for anything. Where did that come from?

Not here "http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=DVXA,DVXA:2005-08,DVXA:en&q=mowry"

mowry,

Only in the last year or so I've been able get into more contact with certain suppliers. Many are very protective about thier sources. I've actually been searching for metal diaphragm sources for a few years, and I must say that when I started out, even I as a local native speaker the same language had trouble communicating. Some factories are just hidden, and to communicate ideas through a middle man really does create problems. People in this industry, have a different way of expressing things from the way we do having received engineering education. They normally use very short expressions for things that are commonly used, and don't really know the proper engineering expression. I once ask an individual driver maker what material they used for the front and back plates, he could not give me an answer. I later found out that most people doing the work really don't know; they just know the name they are used to calling it.

Another person that I talked with about pure beryllium cones mentioned that he once did experience cracking of beryllium cones. If he gave them steady state signals, they were fine. But he came across a condition that would make them crack almost every time. So they abandoned the idea of using them. I recall the cone was probably for a 6~8 inch or so driver.

I was talking with one supplier and we were talking about the good old days when we were young, he mentioned a brand that sounded like "mowry" which I was not familiar with, so I thought I'd ask.