IEC 60318-1:2009 specifies an ear simulator for the measurement of supra-aural and circumaural earphones (used for example in audiometry and telephonometry) applied to the ear without acoustical leakage, in the frequency range from 20 Hz to 10 kHz. The same device can be used as an acoustic coupler at additional frequencies up to 16 kHz. This second edition cancels and replaces the first edition published in 1998 as well as replacing IEC 60318-2, published in 1998. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - an extension of the frequency range to 16 kHz; - a revised specification for the acoustical transfer impedance, including tolerances; - a method for measuring the acoustical transfer impedance; - expanded measurement uncertainties.