For my own quirky reasons, I wanted to make an honest condenser mic like they did in the 1930s (just not as good, I'm sure). My basic idea is to use a sheet of aluminum foil or aluminized mylar hanging about 1mm* from the large pad on the PCB. Foil is fine because I know it's conductive, but I can imagine the problems I'd run into trying to stretch it to the frame as it's fragile. The...