Best material for a polydome

[sagebug]

I find myself with very supple polydomes that cracked right at the glue line of the voice coil. (Basically the dome just peeled right off) This is actually the second pair that has done this to me after using meguiars.
I want to experiment and attach a dome to the lip of the polydome surround and want anybody's idea on what they would use.
I repaired one last night with the cloth dome of a Volvo Dynaudio mid range.(have build pics, will post later) Sounds better than the silicon diaphragms, but not as musical as the originals.
I have seen the dust cap repaired ones, and plan on sending a set in to be done up so I can try those out too.
Just looking for ideas.

P.S. One last quick question.
The cloth domes from the dynoaudio's have tiny pin holes I can see light through. I want to seal the fabric without making them stiff. What could be used?

Appreciate any and all thoughts!

 

[okeeteekid]

I have been using silicon shock oil for rc shocks on mine for about 2 years and mine still look good, only time will tell if they hold up, I was talking to my brother about the stuff some of the guys here use to soften up their polydomes and he told me that those type of conditioners that soften up the domes will eventually make them harder than they were, he said that with rc's they use rubber conditioners to soften up the rubber tires so to get more traction but after a while the rubber starts to harden from using the conditioner, I think he said that the conditioners pull the oils out of the rubber to the surface, I hope that's not the case, I would call someone like simply speakers, they probably have some kind of glue that will work.

 

[okeeteekid]

I bet an infinity cmmd dust cap would sound nice, problem is finding them.

 

[okeeteekid]

How about these, first ones are foam cloth infinity NOS, the second ones are poly, third ones are aluminum, the poly ones look nice.
http://www.ebay.com/itm/INFINITY-3-...hash=item58951a3ffc:m:mFMtt3hvQDwovAy83eV5WiA

http://www.ebay.com/itm/3-25-Poly-D...310957?hash=item43abc03bad:g:aosAAMXQMmJRLTck

http://www.simplyspeakers.com/speaker-dust-cap-aluminum-dc-3a.html

 

[swechsler]

The first domes appear to be what Millersound is using to repair polydomes (too lazy to search for the previous thread, but it was within the last week).

 

[okeeteekid]

The first domes appear to be what Millersound is using to repair polydomes (too lazy to search for the previous thread, but it was within the last week).

They do look the same.

 

[sagebug]

How about these, first ones are foam cloth infinity NOS, the second ones are poly, third ones are aluminum, the poly ones look nice.
http://www.ebay.com/itm/INFINITY-3-...hash=item58951a3ffc:m:mFMtt3hvQDwovAy83eV5WiA

http://www.ebay.com/itm/3-25-Poly-D...310957?hash=item43abc03bad:g:aosAAMXQMmJRLTck

http://www.simplyspeakers.com/speaker-dust-cap-aluminum-dc-3a.html

Yeah, I bought the first two. The Infinity logo cap feels a lot like a stiff polydome diaphragm. It seems more like a felt cap with a foam/rubber texture though.

I've been wondering about glue. I used the nitrile rubber (I think, it's the simply speakers stuff) for the dynaudio dome and wonder if the rubber glue interferes with any sonic transfer from the coil to dome?

Appreciate the reply's everyone!

 

[sagebug]

Here is the Dynaudio domes on my Polydome coil. It's a little "bright" at higher volumes. It sounds better than the white silicon diaphragms I got though. They sound muted with no mid tones.

 

[okeeteekid]

Here is the Dynaudio domes on my Polydome coil. It's a little "bright" at higher volumes. It sounds better than the white silicon diaphragms I got though. They sound muted with no mid tones.

View attachment 657238

View attachment 657239

What did you use for a surround? and how hard was it to center the coil so that it doesn't scrape? I have a couple of spares that I was thinking of rebuilding but haven't found any surrounds yet,

 

[okeeteekid]

The glue that infinity used still feels pretty soft/gummy on my old spare domes

 

[sagebug]

What did you use for a surround? and how hard was it to center the coil so that it doesn't scrape? I have a couple of spares that I was thinking of rebuilding but haven't found any surrounds yet,

I found the surrounds on ebay from some guy that just lists what sizes they are. Standard foam speaker surrounds. These match almost perfect to the original rolls and outside diameter.

To keep everything centered, I built "around" the old stuff.. Pulled the poly from inside coil area out (dome). Took sections of surround out, not enough to make the VC lose it's position though. Attached dome to coil, then outside surround to frame, than I did surround to dome. I went underneath and carefully cut the rest of the poly surround out

 

[okeeteekid]

I found the surrounds on ebay from some guy that just lists what sizes they are. Standard foam speaker surrounds. These match almost perfect to the original rolls and outside diameter.

To keep everything centered, I built "around" the old stuff.. Pulled the poly from inside coil area out (dome). Took sections of surround out, not enough to make the VC lose it's position though. Attached dome to coil, then outside surround to frame, than I did surround to dome. I went underneath and carefully cut the rest of the poly surround out

Sounds like it was a pain to do, my spare polydomes have the dome and surround completely removed so I guess I'm going to have to shim the voice coil somehow to hold it in place, thanks for the info on the foam surrounds.

 

[okeeteekid]

Check out these poly dust caps
http://www.speakerrepairshop.com/in...on=article&group_id=10000064&aid=4325&lang=en

 

[sagebug]

So I have acquired the following:
1. Original Polydome
2. Magicmarksy silicone diaphragms
3. Magicmarksy silicone diaphragm with center cut out and infinity dust cap put on. ( I did this)
4. Dynaudio fabric dome on polydome coil (I did this)
5. Scanspeak replacements
6. Awaiting Millersounds repaired polydomes.

The scanspeak was too loud, but when I put on a 8ohm resistor, DANG it sounds good! I might even say better than the original. Just a little brighter, which I like.
Magicmarksy's silcone speakers were the worst of the bunch, they sound like a polydome with your hand over it! hahaha Such bad quality repairs from him. I could write a diary on all the things wrong, including rubbing voice coils. (360.00 down the drain)
The infinity dust cap on one of his diaphragms really woke it up, but still muddy.
The Dynaudio fabric dome on polydome VC sounds really good, just a little harsh up high. I really think that if one were to find smooth silk domes, it would be a homerun. The dynaudio is very rough textured fabric which I bet leads to the harshness.

I am awaiting Millersound's repaired polydomes before I really do a side by side comparison and crown a winner.

Will update with pictures later.
Once I figure out what mid I will be using, my arrangement will be 8.1's up front, 7.1's in the rear, Kappa Video center and two kappa video centers for front high surrounds. Also, two 10" velodyne subs. I can't wait!!!! Going to take a full weekend to rearrange the living room and set it all up..

I used these resistors on the scanspeaks. Do you think it would be better to use two 4ohm instead of one 8ohm? Just trying to make sure things don't get heated up too bad.

 

[okeeteekid]

I think the caps infinity selected for the kappa polydome mids were chosen to brighten up the original polydome and here's why, I have a pair of the the infinity RSDS polydomes and did a direct comparison to the original polydome using a blackgate high quality cap for the both of them, it wasn't even close the RSDS polydome blows the original out of the water but when I installed the RSDS in my k9 to do a comparison the RSDS sounds a little brighter so I believe that the caps infinity chosen for the k9 complimented the original polydomes lack of brightness being that the dome was so soft, I think if you played around with different brand caps when replacing the polydome you coiuld get better results than the original set up.

 

[sagebug]

Almost looks like the bottom of a plastic bowl. haha! I never see those for sale..

I was wondering why nobody has replaced the polydome with a suitable standard cone mid driver? There is a sealed area for one, and you could even port it out the back.
I did try a IMG driver from my center speaker and it sounded awful, but then again, it wasn't sealed and mounted right either.

 

[okeeteekid]

Almost looks like the bottom of a plastic bowl. haha! I never see those for sale..

I was wondering why nobody has replaced the polydome with a suitable standard cone mid driver? There is a sealed area for one, and you could even port it out the back.
I did try a IMG driver from my center speaker and it sounded awful, but then again, it wasn't sealed and mounted right either.

Lol it does, the dome is poly like the polygraph but the center flat thing is aluminum

 

[sagebug]

I think the caps infinity selected for the kappa polydome mids were chosen to brighten up the original polydome and here's why, I have a pair of the the infinity RSDS polydomes and did a direct comparison to the original polydome using a blackgate high quality cap for the both of them, it wasn't even close the RSDS polydome blows the original out of the water but when I installed the RSDS in my k9 to do a comparison the RSDS sounds a little brighter so I believe that the caps infinity chosen for the k9 complimented the original polydomes lack of brightness being that the dome was so soft, I think if you played around with different brand caps when replacing the polydome you coiuld get better results than the original set up.
View attachment 659188

I would be really interested in knowing where to start on this. When you say different caps, do you mean values? Or brand? I've been wanting to freshen my crossovers up. I read an article on caps and the tests show that you don't always get what you pay for and some where 2-300 a pop!

 

[okeeteekid]

I would be really interested in knowing where to start on this. When you say different caps, do you mean values? Or brand? I've been wanting to freshen my crossovers up. I read an article on caps and the tests show that you don't always get what you pay for and some where 2-300 a pop!

Different brands, they all have their own sonic signature, I think infinity did a pretty good job matching caps to the specific drivers to get them to sound their best.

 

[slimpikkins]

Wow you really tried out a lot of options. I did buy some poly dust caps but they are far to stiff to work. I tried 3 different surrounds 2 foam 1 rubber. The one foam one has a larger roll than the other. The big problem I feel is the relationship of the coil and magnet. Using any of these surrounds places the coil a little lower than the original dome and roll does. They don't seem to bottom out while playing music but it does bother me when you push on them there is less travel is the original. Were you able to overcome this?
Jim