scope:

This standard provides the data, techniques, and rationale for translating head and torso simulator measurements from the eardrum to other acoustic reference points, such as the free field and the diffuse field. It applies primarily to measurements of devices that contact the ear, such as headsets and handsets. It can also be used for devices that do not contact the ear, such as speakerphones and wearable devices. It is applicable to communication and multimedia audio devices over the frequency range of 20 Hz to 20 kHz

Purpose

Common acoustic reference points are needed for comparing electroacoustic performance of handsets, headsets, speakerphones and other kinds of communication devices. It is also needed for comparing communication devices with other devices such as loudspeakers, multimedia terminals and consumer audio equipment. The free field and diffuse field are appropriate reference points because the results relate closely to what we hear. For measurements on communication devices, the free field or diffuse field are more widely applicable reference points than the legacy ear reference point (ERP).