Historical
IEC 60268-4 Ed. 3.0 en:2004
Sound system equipment - Part 4: Microphones
specifies methods of measurement for the electrical impedance, sensitivity, directional response pattern, dynamic range and external influences of sound system microphones, and also gives recommendations as to characteristics to be specified. It applies to sound system microphones for all applications for speech and music
International Electrotechnical Commission [iec]