The G.R.A.S. IEC 318 RA0039 Ear Simulator is an ear simulator with an input impedance closely resembling that of an average human ear. When the RA0039 is coupled to a sound source, the impedance will load the sound source similar to the loading caused by the human ear.
The RA0039 meets the requirements of IEC 60318-1:1998 Electroacoustics - "Simulators of human head and ear - Part 1: Ear simulator for the calibration of supra-aural earphones".
The RA0039 is measured and calibrated according to the ITU-T Recommendation P.57 (08/96) ”Series P: Telephone transmission quality, Objective measuring apparatus: Artificial ears