damping coating substances for speakers' cones ?

Trenner and Friedl make no secret of the fact that they coat some of their drivers with 6 layers of Italian balsamic oil varnish. The brand is even shown on some their pictures.
Trenner & Friedl Lautsprecher

http://www.trenner-friedl.com/download/RA-coating1-HR.jpg

I'm busy trying it on one cheap paper driver (rft) I had lying about . I can offer an anecdote in that I find that after only 2 layers it appears to lower shout considerably. Hard to say if it other parameters deteriorate. It definitely sounds as if it lowers distortions...especially at louder volumes.

Very unscientific I know. But to make it scientific I should compare 50 or so untreated drivers with 50 treated drivers from the same batch..etc., etc...bla bla bla...and measure several parameters...something I am just not able to do. So take all this with a grain of salt.
 

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Having sent some drivers through Klippel scans, I am sure anything you do not the cone that makes the sound different really effects how the diaphragm flexes during vibration. The new wavelet spectrogram capability in SoundEasy really is a valuable tool to help evaluate if you are doing the right thing.
 
I had a can of spray-on bitumen goop for car use, I originally used it for damping pressed steel cones but decided it was too messy. Last time I built some boxes, it turned out great for sticking felt to the ply walls. I must try it on a cone to see what the effect is, next time I have a driver I'm prepared to sacrifice....
 
LTS-50 is nothing like dammar as it doesn't stiffen the cone. The coating is very elastic so the paper cone retains it's original flexibility.

I've tried it with a single coat (my preference) up to insane number of coats which still allows the cone to remain flexible. Not expensive and less than a packet of cigs. Long shelf life as the bottle I have is still good after 7 years.

It's like a condom for cones.... protection but allows flexibilty and enjoyment. ;) If you want stiff, then use dammar. :D
 
I use permatex flowable silicone to coat cloth surrounds and sometimes cones and dust caps. It works very well to control surround reflections in paper cone drivers using rubber surrounds, getting rid of that common 1-2 kHz wiggle. Ive used water thinned mod podge too, but it doesnt dry as flexible. PVA works ok for certain applications but don't let it get exposed to moisture.
 
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LTS-50 is nothing like dammar as it doesn't stiffen the cone. The coating is very elastic so the paper cone retains it's original flexibility.

I've tried it with a single coat (my preference) up to insane number of coats which still allows the cone to remain flexible. Not expensive and less than a packet of cigs. Long shelf life as the bottle I have is still good after 7 years.

It's like a condom for cones.... protection but allows flexibilty and enjoyment. ;) If you want stiff, then use dammar. :D


Hi,


How do you like it, please ? Have you heard goo sounding improvement enough ? Does it tame subtle details or the opposite ?


Btw, has anyone still tried it on metal cones by little touches here and there near and towards the dome cache where the metal cones resonances occur ?
 
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What's bad with Damer and shellacs on paper ? Is it not what all this thing is about ? Making a sandwich with hard exterior and softer paper core, aka sandwich cones ?


I notice the non drying coating is making the opposite with an external damping instead an internal like the best foam core material at Focal, Eton, SB Acoustics...
 
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