Recent experiments by Troels Gravesen have demonstrated that there are advantages in applying damping to the dust cap of the clone's 8535 mid-bass driver. Troels has been working on the resonance problems of the 8535 which he found has "a major intrinsic bump at 3 KHz". In Troels' words, ". . . the coating seems to remove some edginess in the midrange with a more smooth performance and tolerance towards difficult recordings".
The substance used is Damar varnish, which can be obtained from artists' supply shops. The picture attached is from Troels and is of Damar as sold in Denmark. The following is reported with Troels' permission, together with quotes from his e-mails to me.
"As a start you may apply a coating until the dust cap is soaked and leave it there as long as it is not applied outside the dust cap. The effect should be there in a couple of hours . . .
"At the beginning of applying the DAMAR the somewhat porous dust cap readily absorbs the varnish and I continued to apply DAMAR until the surface appeared shining. This doesn't mean 'flooded' with liquid, so 'soaked' may be a little overstated. Actually the amount of DAMAR applied is moderate. I should have applied it in mikrolitre quantities to give recommendations. However, after drying the application is hardly visible. After 1 hour I repeated the application with a final coat of 'less than first time'. After 1 week I don't measure altered performance, so I guess the treatment is stable over time. If the coating is to be removed the dust cap is soaked with turpentine and absorbed with Kleenex tissue."
The varnish sold under the "Damar" brand name in my own country is produced by the company Art Spectrum, and the 100mL bottle I obtained looks physically different. Also, the consistency of the substance is obviously thicker than that sold in Denmark. Applying it as Troels recommended did not produce the same visual results he described. The varnish did not really soak into the dust cap as I applied it, but produced a shiny appearance from the outset. Nevertheless, I went ahead and applied a moderate amount. It took several hours to dry, though it remained slightly sticky in places even 18 hours later. (Mind you, it had been raining here for several days, so that may explain the drying time.) It eventually soaked in to a large extent, though there were still some shiny patches. I reported this to Troels and he recommended the following:
"If your Damar batch seems to be rather thick I'd hesitate to apply a second layer of coating. Maybe one additional layer at the 'center of the centerdome', like 2 cm diameter. Uneven distribution of coating is usually a good thing in disturbing resonances."
My listening tests produced similar results to Troels'. There is a small but definite reduction in midrange edginess, giving a slightly cleaner sound in what I consider to be the clone's main problem area. This benefits "difficult" recordings in particular, so if you are troubled by the clones' midrange this is a highly recommended mod. Just don't expect miracles! The effect is subtle.
The important thing is that you don't apply too much (though the coating is reasonably easy to remove with turpentine if you do) - and that you DON'T get any on the cone itself. (Troels did try damping the cone with Damar, but the results were very negative.)
The substance used is Damar varnish, which can be obtained from artists' supply shops. The picture attached is from Troels and is of Damar as sold in Denmark. The following is reported with Troels' permission, together with quotes from his e-mails to me.
"As a start you may apply a coating until the dust cap is soaked and leave it there as long as it is not applied outside the dust cap. The effect should be there in a couple of hours . . .
"At the beginning of applying the DAMAR the somewhat porous dust cap readily absorbs the varnish and I continued to apply DAMAR until the surface appeared shining. This doesn't mean 'flooded' with liquid, so 'soaked' may be a little overstated. Actually the amount of DAMAR applied is moderate. I should have applied it in mikrolitre quantities to give recommendations. However, after drying the application is hardly visible. After 1 hour I repeated the application with a final coat of 'less than first time'. After 1 week I don't measure altered performance, so I guess the treatment is stable over time. If the coating is to be removed the dust cap is soaked with turpentine and absorbed with Kleenex tissue."
The varnish sold under the "Damar" brand name in my own country is produced by the company Art Spectrum, and the 100mL bottle I obtained looks physically different. Also, the consistency of the substance is obviously thicker than that sold in Denmark. Applying it as Troels recommended did not produce the same visual results he described. The varnish did not really soak into the dust cap as I applied it, but produced a shiny appearance from the outset. Nevertheless, I went ahead and applied a moderate amount. It took several hours to dry, though it remained slightly sticky in places even 18 hours later. (Mind you, it had been raining here for several days, so that may explain the drying time.) It eventually soaked in to a large extent, though there were still some shiny patches. I reported this to Troels and he recommended the following:
"If your Damar batch seems to be rather thick I'd hesitate to apply a second layer of coating. Maybe one additional layer at the 'center of the centerdome', like 2 cm diameter. Uneven distribution of coating is usually a good thing in disturbing resonances."
My listening tests produced similar results to Troels'. There is a small but definite reduction in midrange edginess, giving a slightly cleaner sound in what I consider to be the clone's main problem area. This benefits "difficult" recordings in particular, so if you are troubled by the clones' midrange this is a highly recommended mod. Just don't expect miracles! The effect is subtle.
The important thing is that you don't apply too much (though the coating is reasonably easy to remove with turpentine if you do) - and that you DON'T get any on the cone itself. (Troels did try damping the cone with Damar, but the results were very negative.)
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nadir,
You can adjust the thickness of the DAMMAR varnish by adding turpentine to the product you have in the picture.
I use this tweak on all my other small projects and it work wonder.
You should check out this site:
http://www10.big.or.jp/~dh/tips/dammar.html
Chengs
You can adjust the thickness of the DAMMAR varnish by adding turpentine to the product you have in the picture.
I use this tweak on all my other small projects and it work wonder.
You should check out this site:
http://www10.big.or.jp/~dh/tips/dammar.html
Chengs
Chengs: Yes, I read that on the bottle - but I wasn't aware that it was probably thicker in consistency than Troels' batch until I started to apply it. I did ask Troels whether I should remove the coating and start again with a thinned-down application, but he suggested the second centre-only coating. In any event, it turned out well.
watch out guys
as an artist myself i have used dammar for years and years. i have not put it on any speaker but have used it only many a painting. i would first off say that if you thin it with turp' make sure with out question that it is "pure gum" turps'. back in student days i used the cheap stuff a few times. after a short period of time it will become VERY brittle and the cheap paint thinners will also break down just about anything you brush them on.
check out PURE GUM when you look for your thinner. i have painted oil on paper with it for over 20 years and it is muchless prone to break down paper fibers than standard paint thinners. even those are sold in art shops do to the higher cost of the pure gum. sure the the cheaper will work for today, but.... next year?
as an artist myself i have used dammar for years and years. i have not put it on any speaker but have used it only many a painting. i would first off say that if you thin it with turp' make sure with out question that it is "pure gum" turps'. back in student days i used the cheap stuff a few times. after a short period of time it will become VERY brittle and the cheap paint thinners will also break down just about anything you brush them on.
check out PURE GUM when you look for your thinner. i have painted oil on paper with it for over 20 years and it is muchless prone to break down paper fibers than standard paint thinners. even those are sold in art shops do to the higher cost of the pure gum. sure the the cheaper will work for today, but.... next year?
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