A close-talking pressure-type microphone is anacoustic 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 microphonesare 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 electricoutput substantially corresponds to the instantaneoussound 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.

This document describes a practical and reproduciblemethod of evaluating the performance characteristicsof a close-talking microphone by meansof quantitative measurements of the microphonecharacteristics using a standard artificial voice. Termsassociated with microphones and their testing aredefined. Test procedures, methods of presentation ofdata, and a standard artificial voice are specified. Thetests described in this document involve physical,steady-state measurements only. The data obtainedshould be sufficient to enable an evaluation of qualityand performance of a given microphone in a speechcommunication system. However, since it is sometimesdesirable to obtain a subjective evaluation ofa microphone, a procedure for a qualitative performancetest is described in Appendix I.Several sections of the document specify experimentallimits to account for the effect of the testprocedures on the accuracy of the data. These limitshave been chosen so that results within the range ofnormal engineering accuracy will be obtained.