Alright I've been going crazy with this problem. I'm building an electrostatic loudspeaker. In order to get it right I need to find the Fundamental frequency of the vibrating membrane. This membrane will be of an elastic substance, Mylar. Approx. 5 microns think with a young's modulus of about 4 GPA. How do you go about solving a problem like this? I know the solution will have tension, elasticity in the equation. I guess what I'm really asking is what are the group of equations defining modes of vibrations in elastic membranes. I know it will be in the form of a simple harmonic motion f= 1/2 PI * SQRT(k/m) but there is nothing in that equation relating the restoring force of the membrane due to it's elasticity nor the effects of Air damping it due to drag/viscosity.