RCA 77-D RIBBON MICROPHONE

The 77-D is a high-fidelity ribbon (or "velocity") microphone that was originally designed for television and broadcast studio use. The 77-D was released in 1945 and discontinued in 1955, when its successor the 77-DX was released. The 77-D was advertised as a ‘polydirectional’ mic; what we call today a multi-pattern microphone. The various polar patterns were created by using a tube connected to a chamber behind the ribbon. By rotating a shutter to close off portions of this chamber, patterns could be created from N for non-directional (chamber fully closed), U for unidirectional, to B for bi-directional aka figure-eight (chamber fully open). We acquired this piece from a private dealer in San Francisco.