How to un-wrinkle EMIM diaphragms?

[idadude]

I just bought four used EMIMs that have wrinkled diaphragms. I'm not saying they're just a little wavy, they have some obvious wrinkles, especially in the middle two of the four rows.

I installed them in my RS 2.5s and cranked them up and did not hear any distortion or buzzing, so that's good. So I guess it is more a cosmetic thing, but I would like to get them to be a bit closer to flat if I can get them there. If they warp any more, then that could be a problem.

Anyone know what can be done to flatten these out? I don't plan on doing it right away since there is not a audible problem with the wrinkles at the moment. They would be a mid-winter project when it becomes a bit too cold outside. Break out the iron? What works?

Larry D.

 

[tubed]

Try a hair dryer with discretion.

 

[idadude]

I did try that. I didn't notice any difference. Maybe my dryer doesn't get hot enough.

L.D.

 

[tubed]

I did try that. I didn't notice any difference. Maybe my dryer doesn't get hot enough.

L.D.

I wouldn't sweat it.
I don't think it affects the sound.

 

[savatage1973]

I wouldn't sweat it.
I don't think it affects the sound.

For the moment, probably not a problem, but if they get any worse, they could start buzzing from contact with the cover. I have never done it myself, but I have heard of people disassembling the drivers, pulling the diaphragms and using an iron to smooth them out (with a towel on top--not with the iron in direct contact with the membrane).

 

[idadude]

I was thinking of doing that with some heavy/thick tight-knit t-shirt type material, but I was wanting to hear from someone who had done it and was successful before I'd try it. Otherwise I'll just leave them alone, unless they get worse.

L.D.

 

[savatage1973]

I was thinking of doing that with some heavy/thick tight-knit t-shirt type material, but I was wanting to hear from someone who had done it and was successful before I'd try it. Otherwise I'll just leave them alone, unless they get worse.

L.D.

Well if you bought replacement EMIMs, I am guessing that perhaps you have a couple dead or damaged ones that you could experiment with (doesn't matter whether they work or not), but it could give you and idea if this process "works"--flattens them without damaging the membranes or altering how they fit back into the assembly.

 

[Graz]

Generally the second main failure mode of the EMIM is that the diapragm warms, and the adhesive alows the ali to move on the mylar. Eventually the traces contact and the panel shorts, changing the load and drawing more current, all bad. The best option for using the old parts is to ignore the aesthetics and avoid any heat treatments or manipulation imho!

Test the panel for resistance, what I have measured here falls into the 3-3.5 ohm range, outside of that the unit is not operating as intended. Too low = shorts, to high = solder/joint failures...

Take care - Graz

Well if you bought replacement EMIMs, I am guessing that perhaps you have a couple dead or damaged ones that you could experiment with (doesn't matter whether they work or not), but it could give you and idea if this process "works"--flattens them without damaging the membranes or altering how they fit back into the assembly.

 

[idadude]

I have four EMIMs that have a wrinkle or two in them, but they all test 3.2 to 3.3 ohms. Since they have no distortion (that I'm hearing) I'll just leave them alone and call it good. Thanks for the advice Graz.

Larry D.