Ribbon Microphones: Used extensively in the golden age of radio, Ribbon mics were the first commercially successful directional microphones.  Ribbon mics respond to the velocity of air molecules moving a small element suspended in a strong magnetic field, rather than sound pressure level (SPL), which is what “excites” most other microphone types. In studio applications this functional difference isn’t important, although it can be critical during an exterior location recording on a windy day. Vintage ribbons such as the RCA 44 and Coles 4038 were notoriously delicate; today’s ribbon mics are designed to handle the rigors of daily studio use