IEEE 258:1965

New IEEE Standard - Inactive-Withdrawn.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.

This document describes a practical and reproducible
method of evaluating the performance characteristics
of a close-talking microphone by means
of quantitative measurements of the microphone
characteristics using a standard artificial voice. Terms
associated with microphones and their testing are
defined. Test procedures, methods of presentation of
data, and a standard artificial voice are specified. The
tests described in this document involve physical,
steady-state measurements only. The data obtained
should be sufficient to enable an evaluation of quality
and performance of a given microphone in a speech
communication system. However, since it is sometimes
desirable to obtain a subjective evaluation of
a microphone, a procedure for a qualitative performance
test is described in Appendix I.
Several sections of the document specify experimental
limits to account for the effect of the test
procedures on the accuracy of the data. These limits
have been chosen so that results within the range of
normal engineering accuracy will be obtained.