Yeah I did it - I was able to damage the membrane of one T25B tweeter ... 🙄
Was mounted on a prototype waveguide and got stuck there (to the filler), needed force to get it off. Was in a hurry.
But this gives us a great opportunity to measure the influence of such a damage! What do you think - what happens in the frequency response and THD?
Was mounted on a prototype waveguide and got stuck there (to the filler), needed force to get it off. Was in a hurry.
But this gives us a great opportunity to measure the influence of such a damage! What do you think - what happens in the frequency response and THD?
In the case of Beryllium, I'd be careful playing it loud, as it may shatter in a bunch of pieces, distributing small shards of it all over the place. I'd at least put grill cloth over it.
I had an AL tweeter dome with a ding in it. The dome rang, and though I didn't initially notice it I eventually became sensitized to the sound of it and it became quite grating. Being AL, I tried pulling the dent out with some duct tape, and what I found is that any contact with the dome damped the ringing quite well. I ended up cutting the smallest piece of duct tape I could, a triangle a few mm on a side, and left it stuck to the tweeter, on the dented part. Continued to use it in that state for a few more years.
They won't shatter generally.
It's Materions rolled berylllium foil, same as the Radian. They will deform as in the picture generally.
Unlike CVD diaphragms from TAD, that actually shatter into particles.
While both are BE the mechanical properties are quite different.
Probably it is known, but I still want to remind that beryllium is very toxic. But I don't know. how it is when it is processed in an alloy.
Many greetings,
Michael
Many greetings,
Michael
That makes sense, as the crystalline structure would dictate how the Be will behave under mechanical stress and in which way it fractures.
Yes, to breath Beryllium dust is toxic, a concern for people that process it generally.
Being exposed to a broken diaphragm in your life, your afraid of.
But eating 100 000's of pieces of plastic a year, comes with your food wrapping.
Chemicals, cancer inducing additivies, gene manipulated products etc. Makes noone raise a eyebrow .
1000's die in traffic every day.
Yet you give it no thought when u jump in the car.
How many BE related deaths a year, in the "modern" world?
This fear of BE is not really logical🙃
If one is interested, Bennett Prescott from B&C has a live stream licking a Be diaphragm of CD.
Would it be allowed to produce/sell in EU if it is that toxic?
Would it be allowed to produce/sell in EU if it is that toxic?
I once dented an alumimium dome (SEAS "soft alloy", see my tweeter pole piece drilling thread) and measured it, then tried to repair the dent and measured again.
I suppose beryllium will not be so easy to fix...
here is the measurement (in a wave guide - unfortunately no comparable first measurement, but i suppose there was no sharp resonance peak before):
I suppose beryllium will not be so easy to fix...
here is the measurement (in a wave guide - unfortunately no comparable first measurement, but i suppose there was no sharp resonance peak before):
Well, It happened to me once and I noticed an increase in distorsion at certain frequencies. I brought it back to Bliesma for the dome to be replaced...
I don't think I'd go to that extent. Be is still very toxic. I do agree the dangers are a bit exaggerated. I'd only be concerned more if I had small kids or pets. Be is only a problem if ingested and its unlikely to cause any problems unless it breaks apart into a bunch of tiny pieces and gets into your skin or mucous membranes.
One of my dogs once managed to get hold of a tablet of Tylenol pill which had fallen onto the ground. She sadly ended up with severe liver damage, so I'm always a bit concerned in regards to pets and anything toxic.
Be isn't even remotely an issue unless it breaks apart. In that case a vacuum cleaner would easily get rid of it all.
Sorry people - I was way more busy as I thought. Was not my intention to let you wait so long!
Frequency response:
There is nothing happening up to 13kHz! I know that these dents are not as bad as you maybe think but this comes as surprise for me too.
On the other side - a 6dB resonance at 13kHz ... could be pretty annoying.
THD:
Also surprising! I don't think THD got better through the dent in the 3-5kHz range, that's probably normal differences. VERY little influence (and no - you would not hear harmonics >10kHz ... it's a technical thing)
Frequency response:
There is nothing happening up to 13kHz! I know that these dents are not as bad as you maybe think but this comes as surprise for me too.
On the other side - a 6dB resonance at 13kHz ... could be pretty annoying.
THD:
Also surprising! I don't think THD got better through the dent in the 3-5kHz range, that's probably normal differences. VERY little influence (and no - you would not hear harmonics >10kHz ... it's a technical thing)
And I will send it back for repair and not play around with the membrane and do further experiments (what I would do with an other material).
Beryllium is toxic as fumes and also as dust. I read a datasheet not long ago where you should be carefull in case of fire. But for sure I would not lick it! 🤓
I still have to do some thermic tests which I would have done on an older AL tweeter ... the repair will pay off 😀
Beryllium is toxic as fumes and also as dust. I read a datasheet not long ago where you should be carefull in case of fire. But for sure I would not lick it! 🤓
I still have to do some thermic tests which I would have done on an older AL tweeter ... the repair will pay off 😀
I just wanted to point out it again, and at the same time I pointed out that I do not know how it behaves with regard to an alloy.
Personally, I do not see any relevant advantage in the use of beryllium and will therefore leave my fingers from it.
It is up to each person to know what to do, isn't it? 🤔
Many greetings,
Michael
Personally, I do not see any relevant advantage in the use of beryllium and will therefore leave my fingers from it.
It is up to each person to know what to do, isn't it? 🤔
Many greetings,
Michael
It is foil and the material is rathher ductile, so shattering into dust particles is not a real concern with the foil.
Unless you have someone around that would digest it.
If you take a generic piece of steel and anneal it correct it will become ductile and bendable without shattering.
Take the same piece of steel, heat it to critical and water quench it to 60Rc, and you have a very hard and brittle material that will shatter rather then bend.
The the easiest way to compare Materions BE foil to TADs CVD diaphragms, in a way many can relate to.
Also Vapour deposition of BE is in very fine dust shape as it is produced, and will more easily return to that, wether it is aerosol or liquid deposited.
I'd be a lot more skeptical about the "BE" found in cheap Chinese tweeters etc, which is a thin coating of BE deposited on CU or cu/be.
Or sniffing shattered TAD diaphragms 🙂
And by all means, CVD synthetic diamond, like B&W, SEAS and Bliesma have is in theory the superior material. Not super expensive either, until it comes inside a "hifi" product, with 10x profit margins.
As for the worth of expensive, high end materials. I don't believe it is what makes or breaks a product. There are excellent tweeters made with domes of very different materials from silk to synthetic diamond.
So if your skeptical of BE then keep away from it by all means.
Just replied, as whenever beryllium diaphragms are discussed, this comes up. kind of out of proportion
Beryllium is not unrestricted in the EU,. There is regulations regarding Beryllium in the EU regulations. Just never bothered to look it up.
There has been cases of customs denying to approve imports, because people are writing Beryllim on the packages, and the only thing inside it is a ductile be dome😏
Well food producers and pharmaceutical industry sells you products that slowly kills you, poisons you, cause cancer, drug addiction and a host of other things.
With blessing from the EU and Governments, it has more to do with who gets money, then what is toxic or not.