On a sunny day (Sat, 04 Dec 2010 12:32:34 -0500) it happened Phil Hobbs
wrote in
:

signal. If you rip an electret mic apart, you'll find that it is
metallized on both sides, and the signal is taken between the plates.

It really isn't a capacitance microphone, although its audio
characteristics are somewhat similar. The plates don't move together,
and there's no net field anyway, even if they did. The physics is the
change in the electric polarization due to strain in the material--i.e.
a poled piezoelectric.

Snipped PhD confusion

I do not think that is correct.
http://en.wikipedia.org/wiki/Electret_microphone
Scroll to the bottom, there are 3 types of electret mikes described.
The second one described has the electret film fitted to the backplate, where it does *NOT MOVE AT ALL*.
The third one has the film on the inside front cover where it does *NOT MOVE EITHER*.
That sort of nullifies your argument about strain, except on your mind of course.


insert clue here