Berylium dome tweeter

Looks like a TB 25-1743S to me.

TB partsexpress
my local dealer wants to have 83€, not that bad i think.
do you believe it sounds nearly similar to a focal TBe? FS is really low.

That looks beautiful.

I know nothing about speaker building and normally hang out on the class d or pass labs forums, but this makes me want learn. Seems like this would be an ideal place to start for a high quality 2 way design.

It's the wrong color for beryllium. S/B a dark grey/blue color. Must be over-plated with some other material.

Rob🙂

the only reason i see in covering beryllium is safety.
hopefuly not at the cost of sound quality

Hope Usher starts selling their berylium tweeter and mid.

Data sheet says 'ceramic' dome - guess this is beryllium oxide?
Early rolloff too.

float:
I think you may be on to something here... 🙁
Besides, I hope I'm wrong, but $90 for beryllium seems low to me.

does Beryllium anodise in a similar manner to Aluminium?
If so then it can be dyed in the same manner.

Why does the TB datasheet have so many not/available details? What are they hiding?

Both the TB datasheet and the PE pic show a different faceplate.

A little off subject, but I just recently read stereophile's review of Proac's Response D28 speaker and it was on my mind when I initially responded to this post.

Anyone else think that a similar design, but using this or another beryllium tweeter would be magic? The proac already sounds like an amazing speaker in its own right, with respect to carrying all the advantages of a 2 way, without compromising in the bass. With such a tweeter as this, you could mate it with a larger woofer for even better performance, no? I feel kind of inspired to learn a bit more about speaker building, the proac was basically described in the review as a "textbook two way design." I guess I'm wondering how difficult it could be to build a "textbook design," given that I don't have $6k lying around at the moment.

Beryllium, as I understand it, can not be anodized quite like aluminum, but does develop an oxidation on its surface (its not corroded by this though). This is actually roughly the same color that the Yamaha Beryllium domes turn as they age.

However, beryllium coatings are far more likely, as was used by Yamaha, than pure domes at this price. It's very costly to manufacture and process. I asked one of Focal's engineers a while about the pricing of the Beryllium domes, and if they would be brought down into the cheaper lines. He told me that the problem was that Beryllium is one of the most rare elements on earth, and so will always be costly. Also, the cost of manufacturing is greater. He said that these two things combined to cause a cost of roughly 100 dollars per dome to them. Hence the 1000 dollar up charge from titanium to beryllium at the end consumer level.

Given what I have read and been told about true pure beryllium domes, I'm inclined to believe that this is not a true pure Be dome. I was also told that some so called Beryllium horn drivers actually use a beryllium deposit on a film substrate to form the dome. The engineer that told me this was unwilling to say whose products were made this way, but given who he worked for, and the very limited number of companies making beryllium horn drivers, I was able to make a pretty good guess.

Here's what a 3" Be compression driver dome looks like.

Rob🙂

The Tang Band TW 25-1743Sþ is not Beryllium at all. It's a beryllium copper alloy that is typically 1.8 to 2.0 % beryllium by weight! Here's a message that I sent to Tang Band and their reply.

Dear sirs/madams:

Kindly be advised that the Tang Band TW 25-1743S (http://www.tb-speaker.com/detail/1230_04/25-1743s.htm), which you advertise and represent as a Beryllium Tweeter is not Beryllium. Your claims are false and deceptive. The dome material is actually a common material used in everything from electronic toys to termination in several electronic system products. The material is actually Beryllium Copper, also known as BeCu; CDA 172, CB101, ISO CuBe2, CEN CW101C, A4/2, beryllium bronze and/or Alloy 25. The material is typically only 1.80 to 2.00 % beryllium by weight. To call this material Beryllium is like calling Beer Whiskey but frankly it's statically much worse.

There are really three pieces of evidence.

1. The price is too low for a Beryllium diaphragm.

2. The color of the dome is just not the color of Beryllium. Beryllium is steel gray.

3. The only manufacturer of Acoustic Grade Beryllium Foil (98% or better) on the planet xrayed two samples. This is what they said. "We have performed x-ray fluorescence analysis of the Tang Band "beryllium"tweeter diaphragm. Our analysis indicates that the diaphragm is primarily copper. The technique we used for the analysis is not designed to precisely quantify the composition of the sample, but I am confident that the copper content in the Tang Band tweeter diaphragm is greater than 90%.Therefore, Tang Band may be using Be-Cu for their diaphragms, but I am certain they do not use beryllium as claimed. Please let me know if you would like additional information concerning our analysis of the Tang Band"beryllium" tweeter diaphragm.

The material properties of the BeCu and Be are vastly different.

1. Material Properties summary for Be:
Density 1844 kg/m^3
Young's modulus: 300 x 10^9 Pa
Poisson's ratio: 0.1
Speed of sound: 12800 m/s
http://www.matweb.com/search/DataSheet.aspx?MatGUID=8a6a0df6122349b7bdc92662658d4a4f&ckck=1

2. Material property summary for BeCu

Density: 8250 kg/m^3
Young's modulus: 125 x 10^9 Pa
Poisson's ratio: 0.3
Speed of sound: 3900 m/s
http://www.matweb.com/search/DataSheet.aspx?MatGUID=01a299c56e284436bef9f770a06b668c&ckck=1

The TW 25-1743S seems like a nice product; however, it is being represented as a "Beryllium Tweeter". Please change your description on your websites and in your advertising documentation to "Beryllium Copper Tweeter" at your earliest convenience.

Yours,

Steve Mowry

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

Hello Steve,

Thanks for your comments on the Beryllium, we will correct the name to be "Beryllium Alloy". Our engineering team had ever done the experiment for different Beryllium materials from different vender and source for the dome tweeter and did lots of measurements and listening. The performance, THD, sounding and even the production control, the current one we use fit the best. Therefore, we prefer to use this Beryllium Copper to be the dome for tweeter. Anyway, thanks for your comments.

Sincerely,
Diana Huang
TB Speaker
ISO 9001-2000 certified
E-mail :info@tb-speaker.com
Web : www.tb-speaker.com
Tel : 886-2-26570282

and who gave them ISO certification if they mislead their customers like that?

AndrewT said:

and who gave them ISO certification if they mislead their customers like that?

Click to expand...

The spirit of ISO is to follow procedures to that errors can be discovered as soon as possible, traced to the cause, and corrected for quickly. In this case, it seem like a common way of intoducing products as an indication that this material is an important factor. We see this kind of description like "nano silver", "Nano carbon". "Gortex" etc. in various products; these by no means indicate "pure".

Does ISO test for materials claims or only for safety and if the thing works as advertised?

Can you call a material that is less than 10% beryllium and over 90% copper a beryllium alloy? Not knowing anything about this, I would think that would be a copper alloy.

iso is a quality assurance standard.
False claims cannot be equated to quality assurance.

chrome vanadium is a type of tool steel.
We know it's steel, but the chrome vanadium tells us what differs most from carbon steel.
The same could be said of a copper product that has it's characteristics altered by a small proportion of beryllium.

But, it would be far more honest to say copper/beryllium alloy without specifying are commercially sensitive percentages and go further by explaining why the Beryllium is so important to the copper alloy for their specific use.