New IEEE Standard - Inactive-Withdrawn. A close-talking pressure-type microphone is an acoustic transducer which is intended for use in close proximity to the lips of the talker and is either hand-held or boom-mounted. Various types of microphones are currently used for close-talking applications. These include carbon, dynamic, magnetic, piezoelectric, electrostrictive and condenser types. Each of these microphones has only one side of its diaphragm exposed to sound waves, and its electric output substantially corresponds to the instantaneous sound pressure of the impressed sound wave. Since a close-talking microphone is used in the near sound field produced by a person's mouth, it is necessary when measuring the performance of such microphones to utilize a sound source which approximates the characteristics of the human sound generator.