Anybody else have experience with the silicon Poly Domes from that auction site??

After he lost one of my original Poly Domes and then sent 2 others I had to return due to there poor condition I finally have 2 new Poly Dome K's with silicon domes in my Kappa 8 speakers..The description for the new domes states that they sound just like the originals..Hmmm.. reason for this new thread is to bring up the subject of these silicon domes being sold on that auction site, now in different colors also..Mine have been installed in my Kappa 8's for a few days now and I was hoping there were more people out there who have tried these silicon domes and what their opinions were so we can compare notes and give anybody who is interested in buying them an honest and accurate description that they can find here if they are foresighted enough to do a little research..I didn't have that..The Kappa series, especially the 8 and 9 are a great sounding speaker and one of the best if not the best speakers out there for the money but, the Poly Dome being the achilles heel in that most all of them have turned brittle by now and there are so few options to replace or repair them..The silicon domes by themselves are being sold for $150.00 and already installed in speakers for $300.00..For that kind of money they should sound better than the originals.

I seriously doubt SILICON is the material used.
http://en.wikipedia.org/wiki/Silicon

goodolpg said:

I seriously doubt SILICON is the material used.
http://en.wikipedia.org/wiki/Silicon

Click to expand...

They are silicone, he uses aquarium silicone sealent to glue the voice coil to the dome.

So, in summary, based on reading other threads here on AK, my understanding is that the auction site guy uses silicone since it is easy material to manufacture and create the desired shape in small, non-industrial setting. Silicone is also soft/flexible so that the coil is able to move the dome properly (the problem w/ original domes is that they harden over time).

He also has this nice custom made jig for doing the dome swap:
http://www.youtube.com/watch?v=GpWldxVX4aQ

Now, the problem is that the silicone is _too soft_, so that the center of the dome does not stay in-phase with the ring of the dome (where the coil is), thus understandably distorting the sound.

OP, thanks for creating this thread, I am also very curious to hear other people's experiences regarding this.

@kenyer Since I just stated the problem above, a crazy thought occurred to me...what if you e.g. paint/spray the dome with some light lacquer to harden the silicone dome, particularly in the region within/inside the coil...?

And of course the paint has to be something that does not dissolve silicone...

As a painter, it is my experience that it is very difficult to find any paint that will fully adhere properly to pure silicone. Most times it separates and gives partial coverage.
I would welcome any info concerning a paint that will adhere to 100% silicone.
Sure would make my job easier, especially in bathrooms and kitchens.


I didn't mean to be harsh with the OP, but this discussion would be meaningless if the proper material was not being mentioned.

goodolpg said:

As a painter, it is my experience that it is very difficult to find any paint that will fully adhere properly to pure silicone. Most times it separates and gives partial coverage.
I would welcome any info concerning a paint that will adhere to 100% silicone.
Sure would make my job easier, especially in bathrooms and kitchens.


I didn't mean to be harsh with the OP, but this discussion would be meaningless if the proper material was not being mentioned.

Click to expand...

Maybe silicon would sound better...

I would be afraid of screwing them up worse by trying to paint or varnish them..As they are now I can re sell them like I go them..Actually if you all could see and feel the material you would find that it is thicker than the original material but also yes, softer in that it is flimsy..kind of like thin rubber..and not the same strength all the way across..I expect the maker had no intention of the silicon dome making quality sound but more just making something that looked like the original dome that there was a demand for so he could make some money..Really just the typical state of mind of the majority of sellers on that site..I do give him a pat on the back for taking the first 2 back and sending me another til I was satisfied..Even though he still lost one of my originals.

What's "that auction site"

That auction site is E Bay..After playing the silicon Poly Domes for a few weeks I took them out and replaced them with the original Polys and Lord God..The difference is night and day in the literal sense..The silicon domes are pretty much useless for producing any sound at all..The silicon dome just isn't pliable enough to move and is pretty much just a dome that's there for cosmetic use..They look like a new speaker but don't produce enough sound to even make a comparison to the originals..So there you go

Thanks for posting the results, I kinda thought the silicone domes wouldn't sound no where near as good as the original polydomes but I was waiting to see what you though about them, silicone is a heavy material and is an insulator, now we know why high end speaker company's don't use silicone for drivers.

I'm glad to see the participants in the AK Infinity group can nail a coffin lid on that BS. Thanks again to Kenyer for leading the way. It's certainly too bad it had to be at your expense but I'm sure there are many Kappa owners here (and prospective owners) who appreciate it.

Can someone explain what the function the "poly-dome" is?

Luckily my Polydome mids (6.1) seems to be holding up pretty well after being protected from sunlight most of the time but I do wish to be prepared for their almost inevitable deterioration.

It's the midrange driver.