ACOUSTICS:
Miniaturizing the Mike, in Silicon
Alexander Hellemans
At a recent meeting in Berlin, several groups reported progress in converting the standard elements of a microphone--a vibrating membrane that picks up the sound and circuits that convert the vibration into an electrical signal--into structures on a silicon chip. Silicon microphones may not yet be as sensitive as existing microphones, but they will be robust and cheap, and researchers are confident that they will eventually replace conventional mikes.