If you get the black stuff off the fingers I bet you will see that they have cracks. Looks like a repair job to me.
All of these brands make beryllium drivers, so they know how to design and build with that material.
Maybe they or someone they know are willing help perfect our cloned diaphragm and do small runs of them.
https://sbacoustics.com/?post_type=product&s=beryllium
https://www.eighteensound.it/en/products/hf-driver/1-5/8/ND4015BE
https://www.masterdynamic.com/blogs/know-your-sound-tool/know-your-sound-tool-beryllium-drivers
https://www.focal.com/technologies/the-beryllium-tweeter
https://www.materion.com/en/product...ryllium-products/truextent-acoustic-beryllium
https://vue-audiotechnik.com/beryllium/the-use-of-beryllium-in-transducers/
https://www.paradigm.com/en/passive/persona-b
https://www.revelspeakers.com/info/series-performabe.html
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I guess that the black stuff seems to be epoxy coating used by MeyerSound to hardned the Yamaha diaphragm.
on
you wrote
"Meyer was using the original diaphragms but they limited the excursion by
applying epoxy or the likes to the surround fingers. This had a bit of a negative effect on the sound.
Look at the pic:"
Hi,
I already tried to remove and replace, even to change the driver but always the same Z response.
I will try the hear and measure a tone when loosing/screwing the dia.
What Meyer Sound did was an even distribution on the fingers with an opague (slightly pinkish) Epoxy. Look at the linked Pics again.
I know it is hard to swallow, but these are poorly "repaired" Diaphragms. Repaired is not even the right word, covered up damage describes it better.
If you still can, get your Money Back.
I know it is hard to swallow, but these are poorly "repaired" Diaphragms. Repaired is not even the right word, covered up damage describes it better.
If you still can, get your Money Back.
Angry to read that Radian, 🙁
I think my seller will not want to reimburse me, because he already said that the drivers had been checked by a specialist in Belgium and he paid him €175 for that. Today I tried to realign the VC by checking the impedance curve: it's much better, the curve is clearer but the peak value is only 34Ohm instead of 60 and the Fs is 530Hz instead of 400. The other is still OK. I have to set up a listening set (bass, filter, etc.) to really check their sound compared to the originals.
I think my seller will not want to reimburse me, because he already said that the drivers had been checked by a specialist in Belgium and he paid him €175 for that. Today I tried to realign the VC by checking the impedance curve: it's much better, the curve is clearer but the peak value is only 34Ohm instead of 60 and the Fs is 530Hz instead of 400. The other is still OK. I have to set up a listening set (bass, filter, etc.) to really check their sound compared to the originals.
I still think that if the engineering fees are not too pricey-which could be reduced if the heads here collaborate with the OEM on every detail-that small runs of clones might happen.
Oltos
Did you finaly find a partner who will be ok to rebuilt them?
The price would be anaysed in a second time.
Did you finaly find a partner who will be ok to rebuilt them?
The price would be anaysed in a second time.
Check your messages. Will also add this one to the list, though they may not have the engineering staff to do any prototyping. https://www.simplyspeakers.com/
It seems like most of them require a budget to even look at this project, that is far, far above our measly economy. But I don't think it is difficult to do this yourself. You would need hi-def 3D scanner to copy a healthy diaphragm, hire a 3D artist on Fiver to copy your scan into a 3D model, some good CNC cut molds in aluminium or steel for the dome and VC, some epoxy, laser cutter - some quick digging: https://www.xometry.com/resources/sheet/copper-laser-cutting/
Assuming a pair of 6681b with all fingers intact, has anyone tried them in https://www.athosaudio.com/2021/01/01/tad-th-4001 ?
They would need the right throat adapters which I think Pierre can supply.
But then how difficult to EQ the Yamahas for use in those horns? Pierre said when he EQed the 4001s with his Radian 745Be he gets “You Are There” presentation.
Unfortunately, the better performing T96A was discontinued.
https://www.madisoundspeakerstore.com/bullet-tweeters/fostex-t96a-top-mount-horn-super-tweeter/
But assuming the 4001 horn adapters and EQ go successfully, while this problematic tweeter is badly overpriced, by how much might Troy Crowe’s filter and waveguide make the Fostex T900A about the best tweeter for the Yamahas?
I would go for Jospeh Crowes more organic looking horns. I think the square opposite sides and the 90 degrees corners ruin it for vintage looking horns. When you have a CNC that can make any shape, and then you still mimic a horn which has its shape only because to ease manufacturing in the 70’s, then you are doing it only for sentimentality and not for sound quality. I have tried some A/B tests and ended up with my JMLC-Iwata 300, even if I would have preferred the larger size of the original horns that came with the JA6681B.
The best tweeter horn, I think, is no larger than a JMLC-1000 round horn. I think it could be even smaller. JA6681B works fine up to 7-8000Hz. I wish it would die sooner than at 12kHz, because you have some great options that could start at 7000Hz, to avoid any nasties from the midrange channel. In this sense, I think any good sounding midrange compression driver with good tone could be like a JA6681B. If using active filtering the midrange could be cutoff at about 7000-10000Hz.
The best tweeter horn, I think, is no larger than a JMLC-1000 round horn. I think it could be even smaller. JA6681B works fine up to 7-8000Hz. I wish it would die sooner than at 12kHz, because you have some great options that could start at 7000Hz, to avoid any nasties from the midrange channel. In this sense, I think any good sounding midrange compression driver with good tone could be like a JA6681B. If using active filtering the midrange could be cutoff at about 7000-10000Hz.
I too think it's hard to go wrong with Troy Crowe's horns, especially because, to my (limited) understanding, because they are not constant directivity horns they have very little of that horn colored sound. And I think that's why Troy told me that designs his horns and/or crossovers to deliver more sound stage depth than width. https://cdn.shopify.com/s/files/1/0...ot_2023-10-14_170306_480x480.png?v=1697317415
Conversely, horns like the TH-4001 and A290 may have some degree of coloration (????) but are much closer to being constant directivity horns, thus producing a wider than deeper sound stage. Here's Docali's CD plot of the TH4001 horn https://www.diyaudio.com/community/attachments/yuichi_290_polhrz-jpg.1136807/
https://www.diyaudio.com/community/threads/jmlc-and-yuichi-horns-measurements.395046/page-3
But therefore, would not the A290 and TH4001 produce a more "You Are There" event presentation, while Troy ES450 horn would deliver a more "They Are Here" sound, like Gary Dahl said of his JMLC 425 horns? A question of preferences then, I suppose.
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