SMPTE RP 134 94th Edition, January 12, 1994
Polarity for Analog Audio Magnetic Recording and Reproduction
Includes all amendments and changes through Stabilization Notice (No longer revised / updated) , 2010
This practice specifies the polarity of the signal on the pin connections from a microphone presented with a positive pressure on the diaphragm. It also specifies the resulting positive magnetization when the positive microphone signal is recorded on any magnetic media.
This practice also specifies how this positive magnetization should be played back and fed through a reproducing system to provide a positive sound pressure from the loudspeaker.