Re-coating AUDAX dome tweeters w/measurements!!
- Thread starter elnaldo
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elnaldo
Lunatic Member
I've seen this in some Tannoy tweeters (there is another thread here at AK about them). What I did was to remove with some small tweezers as much as I could of the old material, and paint the exposed cloth with this vinyl product.
You could try some PVA glue, diluted, and do some tests on some fabric to check the thickness, flexibility, and so, and choose the material and dilutioon that gives the best result.
here are picts of those tannoy tweeters, with before-after measurements: One of the tweeters was more damaged, but both showing this problem.
worst tweeter
better dome:
measurement of both tweeters before the fix, you can see a huge difference
Response of both repaired tweeters compared to the best tweeter before the fix:
"repaired" Tannoy domes:
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thanks a lot.
I am from Brazil btw, and couldn't find nothing when googleing for plastificante vinílico
I actualy have an old tweeter of the same type that has amost no resin at all which I will use to do some testing. It might even come back to live...who knows
elnaldo
Lunatic Member
The "goo" I use stays always sticky and flexible. It's very hard to clean, water or alcohol have little effect on it once dry.
It's the material used to seal cloth surrounds on large woofers. If you ask any speaker repair shop in your country, they will know the product. It's not like the original coating in the Tannoy tweeters or in your last pict. That material is dry, and very thin. But sealing the dome as I did restored the tweeters.
It's the material used to seal cloth surrounds on large woofers. If you ask any speaker repair shop in your country, they will know the product. It's not like the original coating in the Tannoy tweeters or in your last pict. That material is dry, and very thin. But sealing the dome as I did restored the tweeters.
most will use products called "gel de borda" or "geleia de borda" in bottles without any label.
there is only one prduct I found:
so the older one uses an acrylic emulsion (basicly a paint finisher?), the newer one I couldn't find out
here is a picture of a surrounding treated with "gel de borda" (not the CiaBond one)
I doubt this stuff is what manufactures use on their tweeters,
on the other hand, looking at the result you posted where one tweeter ended up having mixed coating and the other not so much, it doesn't seam to matter too much. at least if you use DRC.
here is another topic about the subject. some guy says he sucessfully uses silicone: https://www.diyaudio.com/forums/multi-way/79999-soft-dome-tweeter-coatings.html
And this guy used shellac https://audiokarma.org/forums/index...foster-tweeters-model-e-j-k-gens-i-ii.696046/
After researching for 2 days I don't think the material realy matters, as long as it hardens the fabric a little (and seals the fabric).
What realy matters will be the mass after, which will probably make the last octave quieter the more mass. and juding your meassurements the more airtight the more extension you get on the low end
After researching for 2 days I don't think the material realy matters, as long as it hardens the fabric a little (and seals the fabric).
What realy matters will be the mass after, which will probably make the last octave quieter the more mass. and juding your meassurements the more airtight the more extension you get on the low end
elnaldo
Lunatic Member
Now that you mentioned "paint finish", I think there is a product called here "fijador" or "fixer", what you apply to a wall to seal it before painting, looks very similar to this white thing I use. A bit less sticky, but it's water based and very flexible. I have some here at home, I'll try on a piece of cloth and see how it turns once dry.
I'd use that "gel the borda", for sure the material is proven enough.
My goal was not to match the factory material, that would be virtually impossible. My goal was to seal the dome keeping it lightweight and more or less flexible as the original dome was. But I think the main audible difference is because the dome is sealed now. For sure some properties of the material are different, but now the tweeter is usable.
I'd use that "gel the borda", for sure the material is proven enough.
My goal was not to match the factory material, that would be virtually impossible. My goal was to seal the dome keeping it lightweight and more or less flexible as the original dome was. But I think the main audible difference is because the dome is sealed now. For sure some properties of the material are different, but now the tweeter is usable.
it's meassured 2cm from the tweeter, that's why
elnaldo
Lunatic Member
After the years, I discovered the material I use is probably (95% sure) a water based sealant you apply before painting a wall, I don't know the english name or brands for that product, it's probably "Water-Based Primer/Sealer". It's very light, flexible when dry, and not very sticky (better than the original product IMHO)
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