Asymmetric construction induced distortion in electrostatic speakers

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Applying bias to the diaphragm does result in a charge induced negative tension increment.
I posted some plots of this behavior several years ago when I didn't understand what was going on.
arend-jan was kind enough to point me to the Peter Baxandall chapter on ESLs which discusses it in detail.
http://www.diyaudio.com/forums/plan...agm-resonance-change-hv-bias.html#post1884466

Taking a look at the negative stiffness term of the force equation....
F= Eps0*A*2*Vbias²*x/d³

You can see that it increases as square of Vbias, but decreases as cube of D/S spacing. So, for the same panel area and diaphragm tension, if you double the D/S spacing and double the Vbias value to obtain the same efficiency, the negative stiffness term will have less affect on Fs.

Plots comparing negative stiffness trends for different D/S spacing posted here (Attachment 3):
http://www.diyaudio.com/forums/plan...rrent-vs-voltage-drive-esl-7.html#post2366501


In your case you have small areas due to segmentating the diaphragm into smaller sections, and your D/S is fairly large(3-3.5mm I think you had said). So, you may see only very small changes in Fs with bias change until you start getting above 8kV or so.
 
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