The moving membrane in a microphone or loudspeaker.
"Finally, a useful company: I recently had dealings with a company that worked out so well I felt compelled to tell my friends about it. No, I am not a shill - they just did what they said, when they said, and I am very pleased with the final product. Like many, I have a closet full of old LPs, many of which have been replaced by cds. I like a ..."