I hope not, ill update on what happens
I tried the Midwest again just for peace of mind and yea they are... not good.
I hope their foam kits are as good as this midrange driver.. (i have their foam kits for future repairs).
Is the Infinity polydome replaceable with any IMG midrange?
- Thread starter BSEYE
- Start date
I tried the Midwest again just for peace of mind and yea they are... not good.
I hope their foam kits are as good as this midrange driver.. (i have their foam kits for future repairs).
swechsler
Frog Whisperer
You could ask your refoamer what method they used to center the voice coil when installing on the magnets. If they just did it by feel, then there's an excellent chance that's the reason that the output is sub-par. You really need to center it using an audio signal (although I'm not sure what frequency would be appropriate for a midrange; probably something in its lower frequency range).
Needs to be swept through the entire midrange starting around 400Hz through 4-4.5KHz to thoroughly check. Quite often need to also check at 200Hz in order to detect rub on the polydomes.
Well, I've been trying hard to find out whats wrong here and I finally did. Well Actually @seifreit did, I just had to re-read every post everywhere couple if times, dunno why I missed his comment, but I finally noticed it and gave his solution a try. Here is what he said:
This is exactly the issue! I've raised with a millimeter with a simple cardboard, the funny part is that I even used the cardboard from the domes package case and it worked. They suddenly gained something like ~6-8db and I did not even glue the dome, just pressed it with the cover plastic plate.
Well, I did not even glue the dome yet, I will disassemble it now and apply glue. But played few songs on just single speaker and seems more than acceptable. I also ran a dirac so I can see what the frequency response look like and it was pretty much promising. But later when I apply the fix to both of the speakers pass some time for the glue to kick in will make a better comment on that part.
About what I actually did is to cut cardboard 1mm thin in the form of a bagel, just to cover where the dome is glued to the plastic, this rises the entire dome forward and does the magic.
P.S. I am sure if you show my comment to your refoamer he will know what to do. Also this might be better to be 3d printed instead of using cardboard, but I cant wait for that.
About what I actually did is to cut cardboard 1mm thin in the form of a bagel, just to cover where the dome is glued to the plastic, this rises the entire dome forward and does the magic.
P.S. I am sure if you show my comment to your refoamer he will know what to do. Also this might be better to be 3d printed instead of using cardboard, but I cant wait for that.
swechsler
Frog Whisperer
That's not ideal; chances are the inconsistencies won't be the same through the entire frequency range of the Polydome.
Di
did you manage long term success with your kappas with these polydome replacements?
swechsler
Frog Whisperer
I do not have those. I used to have several different pairs of Kappa speakers, but I sold them all except one pair of Kappa 8s, which have the RSDS polydomes.
Well, seems that my guide for doing this is wrong, so I am deleting this and gonna do it again.
deleted guide.
Last edited:
If the Millersound option is not available, then I would certainly try another Infinity midrange.
When I did my RS 7 Kappa speakers, I tried repairing the original midranges, but to no avail. These are difficult to do, and I am no stranger to repairing speaker drivers. In the end, I went with a pair of HiVi 2" fabric domes, Parts Express part #297-716. I was very happy with the sound, and my work colleague that I sold them to is very happy with them as well. What is useful about these is there is no cutting of the cabinets in order to get them to fit. Some new screw holes maybe, but if you ever find a set of the original midranges, you can easily swap them back in.
When I did my RS 7 Kappa speakers, I tried repairing the original midranges, but to no avail. These are difficult to do, and I am no stranger to repairing speaker drivers. In the end, I went with a pair of HiVi 2" fabric domes, Parts Express part #297-716. I was very happy with the sound, and my work colleague that I sold them to is very happy with them as well. What is useful about these is there is no cutting of the cabinets in order to get them to fit. Some new screw holes maybe, but if you ever find a set of the original midranges, you can easily swap them back in.
Yes, I am from Europe and we dont have the Millersound option here. And to be honest I dont think we are that much behind with this fix.
I saw your threat for Kappa 7, the Hivi fits in yours, but wont fit in mine, there will be 2mm of gap, which is a big NO for me. Also looks very different and I can bet they sound very different, it might not be bad, but it sure must be far from whats supposed to be. There are people that dont mind that, but I sure do.
The ring needs to be on the opposite side of the black plastic diaphragm plate to act as a spacer between the complete diaphragm assembly and the magnet assembly. This allows it to be easily positioned during final assembly. The dome needs to be attached to the plastic plate as was done from the factory. This also negates the need to cut the spacer in half to allow the coil wires to pass through
@seifreit Ahh, that totally changes everything. I never thought of that, the alignment of the dome will be much easier, but now I have to align that bottom part too, because when I add 1mm spacer, the fittings there won't reach one another, but its still doable. And it might be even easier, because the bolts will fit them where they must be. What do you think is 1mm enough, how much did you add ?