A microphone with two diaphragms. The second diaphragm may be electronically combined with the first to produce more than one polar pattern. In another type of dual diaphragm microphone, the two diaphragms are for high and low frequencies.
"Thank you so much for the remastering of my old high school choir vinyl onto CD! As I listened to it, it was if I still had my young voice, we were on stage once again, and we were the "kings and queens" of southern Michigan again. Glorious!"