IEC 61094-2:2009 is applicable to laboratory standard microphones meeting the requirements of IEC 61094-1 and other types of condenser microphone having the same mechanical dimensions and specifies a primary method of determining the complex pressure sensitivity so as to establish a reproducible and accurate basis for the measurement of sound pressure. This second edition cancels and replaces the first edition published in 1992. This second edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - an update of Clause 6 to fulfil the requirements of ISO/IEC Guide 98-3; - an improvement of the heat conduction theory in Annex A; - a revision of Annex F: Physical properties of humid air.