noticed a problem with one of my panels

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when I was doing an experiment with my panels I detected a funny sound from the right side,a kinda wind blowing.
I was testing with ultra low frequencies 10 hz and up,and realized that one of the panels was kinda moving more then the others,so i tap on it and all of a sudden i was hearing after each tap a crackling sound,only on one panel.

is it loose?cause i checked all around and saw no tear,hole.but noticed it was moving much more than the others.now that explains when I play low bass this side crackles and pops,anyone have tested how much heat you have to use so the mylar shrinks?
 
Hi,

yeah, with electrostats You get a lot funny effects, some of which even seem unbelievable or unexplainable. Could I tell You stories ;-))

Well, as You reported the membrane of the panel moves stronger than the other? My assumption is, that when You tap the panel (with a fingertip or flat hand?) that the membrane touches the stator. Now You´ll here kind of crackling noise because there will be some low level sparks. As long as there are no ´hot´ and visible sparks this doesn´t damage the panel. Sooner or later the membrane looses its charge at the contact point and it will be pulled back by the stretching forces. This is audible again, because when the membrane is pulled off of the stator there´s a popping sound. The better the stators insulation is the longer the membrane will stick to it.
Your panels seem to have very different stretching forces. You could try to heat the membranes to restretch them to the same point of tension.
You need an hot air gun. Mylar and its derivates shrink at ~150°C.
(You don´t even need a test..its all there ...in the data sheets :D )
Start the gun and wave across the membrane in a zigzagging style while approaching the membrane. When You reached a certain distance/temperature the membrane shrinks. This will normally be by about 5-10cm distance. Now go over the complete membranes.
Normally doing this procedure once should be enough, but doing it several times gives more constant and equal results imo.
Tip: test first with an sample piece of Your membrane!

jauu
Calvin
 
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