IEC 60268-4:2010 specifies methods of measurement for the electrical impedance, sensitivity, directional response pattern, dynamic range and external influences of sound system microphones, and also details the characteristics to be specified by the manufacturer. This fourth edition cancels and replaces the third edition published in 2004, and constitutes a technical revision. The main changes with respect to the previous edition are the following: - correction of noise measurement, - added annex for digital microphones, - added requirement for tolerances in data to be specified. This bilingual version (2010-09) replaces the English version.