Signedbottom of instruments: Western Electric USA 633A
Inscribedinside connector: I G 2 / RBW
FunctionThis microphone was used at Harvard for acoustic experiments. Outside of academia, this microphone was widely used by amateurs, institutions, and professional radio broadcasting companies. As the advertisement says: "Convenient mountings, adaptability, small size, light weight, ruggedness and quality of performance add to its desirability. The 633A will be particularly welcome for use with sound systems in schools, in restaurants, in hotels and in hospitals, by radio telephone amateurs and in commercial broadcasting, particularly for all remote pick-ups."
Primary SourcesWestern Electric, Western Electric 633A Dynamic Microphone (New York, c. 1938).