Material life-expectancy

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Hi Mark,

I got a question regarding the life-expectancy of your drivers. Is material fatigue a problem, provided the speakers are not abused by too loud music or test signals close to fo?
What life expectancy do drivers like the CHR-70 have? Is any information available?

I bought a pair of CHR-70 that I really like. There is only a very small issue I would like to criticise: My parcel came without a sheet of TS-parameter. Of course that info can be found searching the internet, but there are 2 different revisions of that speaker. Some customers may not be clear what speaker they actually have bought.

Thanks for your effort!
 
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Hi chairforce,
sorry for the issues about the two revisions of CHR-70. I never thought about this issue, because we only sold a few of revision one...
For any information about T/S parameters, revision or anything else, please contact me (Email) in the future for detailed information....
I can give exact answers what is in stock in Germany and which revision we sell in Europe...
Cheers,
Nick
 
Hi Mark,
I got a question regarding the life-expectancy of your drivers. Is material fatigue a problem, provided the speakers are not abused by too loud music or test signals close to Fo? What life expectancy do drivers like the CHR-70 have? Is any information available?Thanks for your effort!

Hi Chairforce.
Thanks for raising this issue. Before I begin answering, I have to express some surprise by your choice of words in the title of this thread. Using the word "fatigue" could be miss-interpreted by other DIYers scanning the titles on the list of threads. I've amended the title to more accurately illustrate the matter.

Life expectancy is an question for All audio driver brands and types. To this end, the issue maybe best addressed in the various sub-sections of the Loudspeakers section of this forum. You'll also need to address the issues of end-user operation and box optimisation. Both these issues are usually the major factors determining driver service life.

The CHR-70 drivers are quite robust. You might want to to talk to DIY member Tresch. He can tell you just how much punishment his CHR drivers have taken and still carry on performing. All my drivers are capable of many years of faithful service when treated with respect. I've run accelerated life tests on drivers that simulate 12 years of service operation. These test drivers are still good for normal operation.

Thanks

Mark.
 
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Mark, I wanna know that too. Are your aluminium coned speaker deep anodized? If they are, I'll feel better as I will assume the cone is durable. :)

Boris,
So you're an expert on cone design?

First, none of my cones are made from "aluminium".

You'll have to explain to me in precise engineering detail how a "Deep anodized" coating changes the resistive stress load characteristics of a low mass cone; And how such "Deep"coatings won't impede emittance and resonant properties of said cone. Perhaps my 30+ years in the field of engineering design mean that I still don't know anything.

I believe you mean well but next time, ask a question rather than "lecture" me.

Mark.
 
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Mark,
First I did not mean to pretend to be an expert, but by the appearance of your speakers (and also the Jordan ones), I assumed that they were aluminium as it looked like so and aluminium is one of the most commonly used metal for making speaker cones. I'm sorry if it seems like nonsense. I just found from your site that they are alloys ( I assume it's your special recipe), so I'm sorry for my mistake.

Regarding the "deep anodized" matter, we all know that it is a common treatment for aluminium articles. By anodizing the metal (e.g. an aluminium speaker cone), you can form a relatively thick (but still invisible) layer of aluminium oxide. This layer is actually a kind of ceramic and protects the metal it surround, and as speaker cone material a ceramic coated aluminium cone can improve damping and at the same time increases the strength of the cone (ceramic has higher tensile strength than metal but is more brittle, and luckily the anodization without heating does not form well bonded ceramic but rather micro crystals). This type of cone treatment is widely used in Acoustic Energy Klipsch speakers and also Accuton (aka thiel and partner) and not so deep anodization is even used for making the tin foil (which is in fact aluminium) we use for warping the very gratin we have for dinner.

Mark, I am sure you know more in speaker design than I do, and I know you dislike being "taught" in speaker design, but I do not mean to teach or insult you in any way. I am just being curious and giving my own opinion. I haven't studied engineering although I would like to learn it from you. I hope we can chat on acoustic engineering and other matters as well.

Best regards,

Boris
 
BTW, Mark, I DO intend to buy a pair of CHR70 but I'm not free for a while. I'll be receiving my exam results and have to work on my university choices repositioning so please pardon me for being not able to buy it for a while. ( You see, I'm just an innocent student who is also an audiophile. I am not an attacker! )
 
Mark,
First I did not mean to pretend to be an expert, but by the appearance of your speakers (and also the Jordan ones), I assumed that they were aluminium as it looked like so and aluminium is one of the most commonly used metal for making speaker cones. I'm sorry if it seems like nonsense. I just found from your site that they are alloys ( I assume it's your special recipe), so I'm sorry for my mistake.
Regarding the "deep anodized" matter, we all know that it is a common treatment for aluminium articles. By anodizing the metal (e.g. an aluminium speaker cone), you can form a relatively thick (but still invisible) layer of aluminium oxide. This layer is actually a kind of ceramic and protects the metal it surround, and as speaker cone material a ceramic coated aluminium cone can improve damping and at the same time increases the strength of the cone (ceramic has higher tensile strength than metal but is more brittle, and luckily the anodization without heating does not form well bonded ceramic but rather micro crystals). This type of cone treatment is widely used in Acoustic Energy Klipsch speakers and also Accuton (aka thiel and partner) and not so deep anodization is even used for making the tin foil (which is in fact aluminium) we use for warping the very gratin we have for dinner.
Mark, I am sure you know more in speaker design than I do, and I know you dislike being "taught" in speaker design, but I do not mean to teach or insult you in any way. I am just being curious and giving my own opinion. I haven't studied engineering although I would like to learn it from you. I hope we can chat on acoustic engineering and other matters as well.

Best regards,

Boris

Hi Boris,
I understand your sentiments. Yes, you're young (wish I could turn my clock back). Being young is good but it also means you've yet more to learn and then to apply your knowledge. Your previous post was not so good because you've not done enough reading on the function of wide band and full range acoustic emitters.


1 - "As we all know" You're sure about this? Everyone knows about anodizing? I'm sure this is not the case. Anodizing is allot more complex than your description suggests.
2 - Oxide? That's one method, there are others.
3 - Thick? This is not the case. If it were, I would have given up on metal cones long ago.
4 - Invisible? This is not the case. Many processes are visible.
5 - Ceramic has higher tensile strength? Not necessarily so, depends on the stress-load direction and how this is measured, shock load, bending force and compliance, to name but a few.
6 -Acoustic Energy Klipsch speakers and also Accuton? These aren't FR drivers. Their cones aren't required to produce wide-band emittance.

Your missing the essential point. There's no one single factor that can determine the cone's behaviour. If I "Deep coat" (as you put it) the cone, there's no automatic guarantee that this process will increase the driver's service life. The one thing that I can guarantee is that you can kiss good-by to part of the cone's resonance properties.

You need to take a step back and do much more research into the design and function of full range emitters. Your making too many "statements" posing them as "facts" without properly understanding the involved physic's, the engineering, production processes and driver operation.

I don't want to put you off from contributing but now is the time to listen and learn, rather than continue to jump in "feet first". Make fewer assumptions, ask more questions, do more research.

Thanks

Mark.
 
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BTW, Mark, I DO intend to buy a pair of CHR70 but I'm not free for a while. I'll be receiving my exam results and have to work on my university choices repositioning so please pardon me for being not able to buy it for a while. ( You see, I'm just an innocent student who is also an audiophile. I am not an attacker! )

That's OK Boris. You're welcome to come and listen to the drivers in Chai Wan when you have the time. I understand your not an "attacker". That's why I'm trying to help you better focus your youthful energy. You live in Hong Kong SAR. It's a place that "takes no prisoners" if you get it wrong it your future professional life. Take more time, ask more questions, consider issues more carefully before making decisions and publicising opinions.

Cheers

Mark.
 
Mark, thanks very much for your lesson. I think I can understand what you're saying now. I will try to be humble and read more before suggesting these.

I would however want to know why you would have given up on metal cones if the anodized layer can become thick though...

BTW, I've heard that the cone profile also affects the cone behaviour. Is the "exponential" profile more suitable as a full range driver than a straight profile one?
 
Mark, thanks very much for your lesson. I think I can understand what you're saying now. I will try to be humble and read more before suggesting these.

I would however want to know why you would have given up on metal cones if the anodized layer can become thick though...

BTW, I've heard that the cone profile also affects the cone behaviour. Is the "exponential" profile more suitable as a full range driver than a straight profile one?

Boris, It's not about teaching you a "lesson" or trying to make you humble.

I'm trying to encourage you to be more investigative, learn more, further develop your knowledge base, then you'll be in a better position to make assessments.

It's been one of my issues that in Hong Kong, under-graduate and post-graduate education does not do enough to help students learn the powers of investigation. When I was a post-graduate in the UK, the first thing we were told was to: "make a contribution to original thinking". Its quite a challenge for students but a worthy one. It means you have to carefully propose any theory or ideas, offer testing and evaluative solutions to prove said theory/idea is viable; And VERY carefully evidence (et.al) your scholastic work.

You seem like a bright guy, a student with much potential, hence my efforts to get you to think more.

So, why have I given up on thicker coatings? Re-read my previous posts, there are several clues. Do some web research on acoustic emittance, cones and full range drivers. Come back to me on this thread with your findings and I'll help you further. But I want to see you try to figure out what a cone does and how it works.

Cheers

Mark.
 
Mark, I think I know the answer now, please let me know if it's the correct one. :)
First, the anodized layer is hard but brittle so it will stop performing as a perfect piston at higher frequencies and is prone to have a breakup mode in those frequencies, something like 6kHz to 8kHz so that's why those deep anodized cones are usually used in woofers. (Just a conclusion after reading about the aluminium woofers from SEAS and peerless) Such peaks caused by the cone breakup mode is a nightmare for full range drivers. With a more elastic coating, there will be less ringing and softer peaks.

Best regards

Boris
 
I also say thanks for the information.

I just wanted some information about about the duration of drivers in general and about the ones I have already bought. Just in case my posting sounded derogatory, that was not my intention.

I am glad to hear that the ageing of your products is simulated.
 
Mark, I think I know the answer now, please let me know if it's the correct one. :) First, the anodized layer is hard but brittle so it will stop performing as a perfect piston at higher frequencies and is prone to have a breakup mode in those frequencies, something like 6kHz to 8kHz so that's why those deep anodized cones are usually used in woofers. (Just a conclusion after reading about the aluminium woofers from SEAS and peerless) Such peaks caused by the cone breakup mode is a nightmare for full range drivers. With a more elastic coating, there will be less ringing and softer peaks.
Best regards
Boris

Hi Boris,
You're beginning to have an idea but you still need to go back to the primary form and function of a cone. Continue researching. Concentrate on the physical properties that a full range cone needs to have in order to function.
Cheers
Mark.
 
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