This Recommendation specifies the electroacoustic characteristics of the head and torso simulator (HATS) for telephonometric use. Both sound emissions and sound pick-up characteristics are specified; the free-field acoustic diffraction is specified as well.
ITU-T P.58-2013 Referenced Document
ISO 4869-1:1990 Acoustics; hearing protectors; part 1: subjective method for the measurement of sound attenuation
ITU-T P.50-1999 Artificial Voices Study Group 12; Covering note: 5/25/2000