close-talking sensitivity

6.61  close-talking sensitivity. Of a microphone, for a specified frequency, quotient of the output open-circuit voltage by the sound pressure, at the position previously occupied by the microphone reference point, in the undisturbed sound field produced by a specified source that simulates the acoustical characteristics of a human head and mouth. Unit, volt per pascal (V/Pa).

Annotation 1          If the load impedance is other than that of an open-circuit, it should be specified.

Annotation 2          This definition is relevant only to microphones used close to the mouth.