Electret Driver Remagnetization
Feb 10, 2014 at 7:06 AM Thread Starter Post #1 of 6

myheadHz

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Greetings all, first up.... is this possible???
 
In theory I think it should be, but in practice maybe not since I can't find any info on this process. I would like to try it with an old electret that I have which appears to be very quiet and then sound distored on max volume (and it stil sounds like I'm listening to it through a thin wall). I'm assuming this is the problem with these electret headphones. Has anybody tried this? If at all possible?
 
The first two methods I am going to try, probably with each driver so that I could compare.
 
1. Rub a magnet till I get bored over the appropriate object.

2. Wrap a load of copper wire around the object, apply electricity and then leave over night(s).
 
I say object, as I haven't opened them up yet, so not too sure what will need magnitising at the moment (a compass should tell me though!).
 
Just thought I would ask in advance in case there are any tips from anyone? Any help would be appreciated! Many thanks!
 
Feb 10, 2014 at 10:21 AM Post #2 of 6
  Greetings all, first up.... is this possible???
 
In theory I think it should be, but in practice maybe not since I can't find any info on this process. I would like to try it with an old electret that I have which appears to be very quiet and then sound distored on max volume (and it stil sounds like I'm listening to it through a thin wall). I'm assuming this is the problem with these electret headphones. Has anybody tried this? If at all possible?
 
The first two methods I am going to try, probably with each driver so that I could compare.
 
1. Rub a magnet till I get bored over the appropriate object.

2. Wrap a load of copper wire around the object, apply electricity and then leave over night(s).
 
I say object, as I haven't opened them up yet, so not too sure what will need magnitising at the moment (a compass should tell me though!).
 
Just thought I would ask in advance in case there are any tips from anyone? Any help would be appreciated! Many thanks!

 
Electrets dont rely on magnetism. 
They rely on a modified electrostatic principle, using a permanently (well, not really permanent) charged membrane to save the cost & complexity of a bias supply. This is cool because it simplifies the little transformer boxes they are normally supplied with.  
 
Take good detailed pictures of the drivers for wikiphonia. 
 
http://wiki.faust3d.com/wiki/index.php?title=Main_Page
 
Feb 10, 2014 at 11:46 AM Post #3 of 6
Doh...Ah yes, my confusion...its not the magnet(s) that are failing its the electric charge.... in which case, can I re-charge an electret driver? Would I be along the correct lines in saying Electrostatic Induction to be a start.... this seems fairly simple in principle? But I'm thinking it is not possible since no one has mentioned it before. Thinking about rubbing my feet on the carpet for ages and then touch my driver!!! Many thanks for your repsonse nikongod.
 
Feb 10, 2014 at 8:37 PM Post #5 of 6
In principle, of course you can recharge it because it was charged in the first place. It'll be quite the project though! You'll have to disassemble the driver exposing the fragile diaphragm. When the driver is all built, it's shielded by the stators so you won't be able to charge it.
 
I'm not sure how headphone diaphragms were charged, but you'll at that point have a thin plastic film that needs to be charged. You might be able to do this by rubbing and exploiting the triboelectric effect. You'd definitely run the risk of damaging it by rubbing it with anything, though, since it is a thin film. The only really safe way I can think to do it would be by corona charging which would require putting it in close proximity to a high voltage corona discharge.
 
Afterwards, put it all back together and with a ton of luck it'll work. You'd likely have to do both drivers at the same time by the same process since you need them to be balanced in charge. You might even need to fully discharge both to have them starting in the same state, not sure. I can't think of any good way to discharge them short of rubbing them with sharp metal points, which obviously would destroy them.
 

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