Could doing so risk changing the tonality of the 6681B? Might not be wise. Beryllium's likely more expensive than carbon but, happily or not, the market for replacement diaphragms for this driver is obviously hardly huge, so smaller runs of them will cost us more. I for one could live with that.
As for Radian, they are hardly the only compression driver brand in the world; check out the 10 or so brands I listed on the previous page. What matters now is:
Finding a brand among these and others you may know of who are willing and able to clone the diaphragm from the blown one that you or someone will send them. Agree to a final engineering and prototyping fee that ~ 20 or more of us can afford-AND give us a ballpark figure on the price per unit. The S-shaped beryllium suspension piece, which is probably the most difficult part to clone, could likely be easily laser etched via CNC, as Rewind has postulated.
The brand then sends the prototype to one of us who is best equipped to run all response, impedance, distortion and other tests on it. Then if the diaphragm measures and sounds as good as the original we all place our orders and everyone wins.
Then to insure continued availability, we can post a new thread here and at audioasylum, audiocircle, AVS, vintagespeakers.com and other diy speaker forums.
Subject: Yamaha JA6681B Cloned Diaphragms Now Available. We pat ourselves on the back for making it happen and post the link to the brand.
So now is the time to start clicking on those links to those brands and call or email their marketing department. And to show that it's not just you making this request, sendig them the link to this page should also aide in convincing them that there is real and potentially sizable demand for this diaphragm.
The beryllium-copper used in the fingers is not very expensive, it is not like using pure Be for diaphragms where the production process is complex and expensive. It is used in many products, it is very common in connector terminals for instance. It makes the copper easier to machine, stronger etc. Be content is normally lower than 2%.
//Anders
//Anders
Hi, I am having a 2.5 m deep midbass horn laser cut, but until it is done, I am finishing a ”subwoofer” tower with two Seas W26FX002 on each side and the Ja6681B in an Iwata 300 with the HF10AK in a JMLC 1000. I dabbled with a 200Hz horn from JBL but it was too small.
Okay, assuming that the fingers and the rest of the diaphragm is not expensive or difficult to build, and that at least one OEM from my list here is willing to clone the diaphragm, How likely would someone here loan out their blown diaphragm to the OEM to make it happen?
Didnt you at one time use Raal tweeters?
How is the HF10AK comparable to the Raal?
Is the JMLC the E version?
IF you had read my post correctly you would have understood that I had asked that one or more of us might agree to loan out a blown
diaphragm-which is essentially useless but would likely be required for OEM to examine and evaluate if we were to have any hope of it being accurately cloned.
Yes, the Raal was nice, but JA6681B is much better without any autotransformer, L-pad or even series resistor, which was be required when playing JA6681B with the Raal tweeter on the same amplifier. I will try the HF10AK more soon. My first impressions are that HF10AK is smooth and clear, while Raal is a bit timid, but possibly more detailed. Maybe I can hear a slight roughness with the HF10AK, due to some breakup, or whatnot.
I have the regular round JMLC-1000 horns. I also tried JMLC iwata 600 with the HF10AK and the JMLC-1000 sounds better with the HF10AK. I use JA6681B in Iwata 300 and possibly 600. We will see. Right now this 2-way is playing the socks of anything I have heard: JA6681B in iwata 300 and four W26FX002. The woofers are surpsingly articulate for being slow home hifi bass woofers.
I have two damaged diaphragms that can be loaned out. One with a working suspension, but broken dome. And one with a complete dome, but slightly deformed copper suspension.
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That would be great if you or someone can then loan a blown one out. If yes, then I will pitch the request to all of those OEMs. Hopefully, at least one will have the expertise to clone it and, for a reasonably affordable fee, produce a pair of clones for us to run all of Troy Crowe's measurements and then do the listening sessions.
Then if our panel of listeners find the diaphragms to sound truly authentic we can all agree to do one big group buy, to induce the OEM to make sufficient quantities to minimize per unit cost. Then if everyone's happy with their first pair they can opt for at least a second pair for insurance. I sure would.
That would be great if you or someone can then loan a blown one out, especially one with the fingers at least partially intact. If yes, then I will pitch the request to all of those OEMs. Hopefully, at least one will have the expertise to clone it and, for a reasonably affordable fee, produce a pair of clones for us to run all of Troy Crowe's measurements and then do the listening sessions.
Then if our panel of listeners find the diaphragms to sound truly authentic we can all agree to do one big group buy, which should induce the OEM to make sufficient quantities to thereby minimize per unit cost. Then if everyone's happy with their first pair they can opt for at least a second pair for insurance. I sure would.
Of course, there's no guarantee that any OEM will agree to act on our request. Time will tell.
I can't comment on that technique; my DIY skills are too limited. But it might be best to duplicate his set up as all the measurements Troy ran showed very impressive performance, including the distortion tests-and where he was able to reduce distortion by ~ 10x by adjusting screws and then omitting to of them.
No doubt, several 6681B owners on this thread can run all of these tests on do the same distortion reducing tweak on the cloned pair.
FWIW, the horns for my Yamahas which Troy will design the crossover for to blend with a pair of Great Plains Altec 416-8B midwoofers in 3 cu ft sealed boxes will be these https://www.athosaudio.com/2021/01/01/tad-th-4001/
The 4001 has a different exit angle than the JA6681B. I would check out any midrange horn from Autotech.