Possible replacements for 3 inch Polydome

drumman2112

Active Member
Soon I will begin restoring a pair of Kappa 8. Both polydomes are shot and need to be replaced. As we all know, Infinity no longer makes replacement diaphragms. The replacement that Orange County is selling is advertised to be a direct drop in replacement. Has anyone tried one? I found this one today and was thinking this may be a contender. What do you think?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-857
 
Soon I will begin restoring a pair of Kappa 8. Both polydomes are shot and need to be replaced. As we all know, Infinity no longer makes replacement diaphragms. The replacement that Orange County is selling is advertised to be a direct drop in replacement. Has anyone tried one? I found this one today and was thinking this may be a contender. What do you think?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-857

They are very different...Kappa's are dipole speakers the replacement is Not rear firing like the originals, impedence is also different , This will affect the crossover and adjustments on the pots may not compensate acuratly.. so if you make a change do it to both speakers. But IMO keep them original either try to find a replacement on the bay or have that guy in hong kong switch the dome out.....FYI as long as the dome is pliable they will not sound any different....the color has no effect on the sound quality...
 
Orange County Speakerworks offers a drop-in replacement for the 3" Polydome here. This driver is an exact fit, and no modifications are needed to the crossovers. It's made by Vifa. It's a little pricey at OC, but supposedly well worth it. These can be found elsewhere for less.
 
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As long as the voice coils are intact, Polydomes can be re-built, very close to original. There is a guy here in Hong Kong who does these; he did the ones on my Kappa 8s, and they're fine. The replacements are black, not off-white, but otherwise quite similar to original. He also rebuilt Polydomes for AKer Soulster42. Look here for details: http://www.audiokarma.org/forums/showthread.php?p=477588 .

Just presenting an option. (No vested interest or affiliation.)
 
Since Scan-Speak and Vifa are now the same company, the Madisound Scan-Speak mid and the Orange County Vifa mid are one and the same. There's even a note to that affect on the Madisound site:

"(formerly Vifa D75MX-41-08, D75MX41)"

While a "drop-in" replacement physically, I still have to wonder how the impedance differences effects both the midrange sensitivity and the crossover slopes? But, failing a rebuild of the original dome, or used ebay buy, there's few other options for Kappa owners...
 
They are very different...Kappa's are dipole speakers the replacement is Not rear firing like the originals, impedence is also different , This will affect the crossover and adjustments on the pots may not compensate acuratly.. so if you make a change do it to both speakers. But IMO keep them original either try to find a replacement on the bay or have that guy in hong kong switch the dome out.....FYI as long as the dome is pliable they will not sound any different....the color has no effect on the sound quality...

I have Kappa 8s. The mid doesn't fire through the back on the cabinet like the 9s. The Hong Kong guy looks like he does some great work but I wonder how long the turn around time would be. I have to replace or repair both polydomes. Of course I would like to stay all original or have them rebuilt. I don;t think my voice coils are shot. I have only has these kappas for two weeks. Is there a way to test or check the voice coils without running sound through them?
 
Since Scan-Speak and Vifa are now the same company, the Madisound Scan-Speak mid and the Orange County Vifa mid are one and the same. There's even a note to that affect on the Madisound site:

"(formerly Vifa D75MX-41-08, D75MX41)"

While a "drop-in" replacement physically, I still have to wonder how the impedance differences effects both the midrange sensitivity and the crossover slopes? But, failing a rebuild of the original dome, or used ebay buy, there's few other options for Kappa owners...

You are right. What's funny is the significant price difference between the two. I am VERY skeptical of buying from the bay when I can tell how old there are and if they have been rigged. You would swear they have gold in them for what they are getting for them.
 
As long as the voice coils are intact, Polydomes can be re-built, very close to original. There is a guy here in Hong Kong who does these; he did the ones on my Kappa 8s, and they're fine. The replacements are black, not off-white, but otherwise quite similar to original. He also rebuilt Polydomes for AKer Soulster42. Look here for details: http://www.audiokarma.org/forums/showthread.php?p=477588 .

Just presenting an option. (No vested interest or affiliation.)

do you know what he charges?
 
Fyi

I have Kappa 8s. The mid doesn't fire through the back on the cabinet like the 9s. The Hong Kong guy looks like he does some great work but I wonder how long the turn around time would be. I have to replace or repair both polydomes. Of course I would like to stay all original or have them rebuilt. I don;t think my voice coils are shot. I have only has these kappas for two weeks. Is there a way to test or check the voice coils without running sound through them?

Just so you are aware...the polydomes from the later Kappa speakers will also be a match for your speakers too. The only real difference is that the later models have a wire mesh under the dome other than that they are the same driver..Be patient they do show up on the bay often enough. Probably less $$ than having yours shipped to H.K. and back...But if you have the money a new dome sounds awesome....I think what they do is swap out the original dome with a vifa dome on an existing polydome driver.....using the original voice coil and magnet so the impedance doesn't change ....
 
Just so you are aware...the polydomes from the later Kappa speakers will also be a match for your speakers too. The only real difference is that the later models have a wire mesh under the dome other than that they are the same driver..Be patient they do show up on the bay often enough. Probably less $$ than having yours shipped to H.K. and back...But if you have the money a new dome sounds awesome....I think what they do is swap out the original dome with a vifa dome on an existing polydome driver.....using the original voice coil and magnet so the impedance doesn't change ....

I can't sell myself on buying used polydomes off of the bay, too much uncertainty. Using the VIFA type mid parts and frankensteining something together is a possibility for me to since since the voice coils are in tact although I feel apprehensive about taking it on myself. I have been surfing around looking for any info from someone who was successful doing it. Anyone know of a place in the US that would do it?
 
As long as the voice coils are intact, Polydomes can be re-built, very close to original. There is a guy here in Hong Kong who does these; he did the ones on my Kappa 8s, and they're fine. The replacements are black, not off-white, but otherwise quite similar to original. He also rebuilt Polydomes for AKer Soulster42. Look here for details: http://www.audiokarma.org/forums/showthread.php?p=477588 .

Just presenting an option. (No vested interest or affiliation.)

Uhh, that link points towards a thread about video games. I'm quite interested in the possibility of having the diaphragm replaced though - could you fix the link or post the details here?
 
For Christmas my wife got me Vifa polydome replacements and a refoam kit from Simply Speakers. Won't be long until I get these boys up and running!
 
Soon I will begin restoring a pair of Kappa 8. Both polydomes are shot and need to be replaced. As we all know, Infinity no longer makes replacement diaphragms. The replacement that Orange County is selling is advertised to be a direct drop in replacement. Has anyone tried one? I found this one today and was thinking this may be a contender. What do you think?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-857
Try to find the ORIGINAL version VIFA D75MX (no numbers after the MX) with the clear poly domes. The they sound much better than the later (black) fabric versions. The Poly dome is much much lighter and has a more detailed/natural sound. It has a tighter HF frequency range than the later version and must cross it over to HF around 3500-4500 for best results. It's a sweetheart mid and better than the Morel 55 when used properly.
 
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