Method for Measurement of |E′/I′| in the Reciprocity Calibration of Condenser Microphones

A simple method is described for accurately measuring the ratio of the driving current through a capacitor‐type sound source to the open‐circuit voltage of a microphone used as the sound receptor. Determination of this ratio in a reciprocity calibration procedure eliminates the need for measurement of the capacitance of the reversible microphone.