Standards Development

Scope

This part of IEC 60318 describes an ear simulator intended for measurement in the frequency range from 20 Hz to 20 000 Hz. The ear simulator is suitable for measuring earphone devices, e.g. hearing aids, headphones, headsets and for integration in Head and Torso simulators to simulate the complete ear canal and the outer ear. The Full-audio-band anthropometric pinna and ear simulator has an anatomically shaped pinnaand ear canal of a typical human adult, similar to the geometry defined in [ITU -T Rec. P.57, Type 4.3 Ear Simulator]. The outer part of the pinna and ear canal may be separated from the inner part of the ear canal which  also contains an eardrum impedance simulator and a microphone. In this configuration the inner part can be used as a standalone device like the occluded-ear simulator in [IEC 60318-4]. The acoustic transfer impedance of the inner part defined in this standard simulates a typical human ear in the full audio band. When coupled together the Full-audio-band anthropometric pinna and ear simulator can be integrated in Head and Torso simulators to simulate the acoustic performance of a full typical human adult. This is further specified in [IEC 60318-7]. It can also be used to show the effect of possible leakage between an ear mould and a human ear canal. The Full-audio-band anthropometric pinna and ear simulator specifies one specific geometry for the pinna and ear canal and one set of acoustical properties. Individual ears of humans will differ from these specifications and therefore the performance of a device on a specific human ear may differ from the performance on the simulator.

Purpose

Ear simulators are widely used for testing headphones, hearing protectors, hearing aids and many other acoustical devices. Presently the 60318-4 Occluded ear simulator is used for many of these applications, but this standard covers only the innermost part of the ear canal and does not give specifications for the outer part of the ear canal and the pinna. The 60318-4 Occluded ear simulator was originally developed in the 1979’ies and advances in detailed knowledge about the acoustics in ear canals since then, as well as new production techniques, enables the design and specification of new couplers that may more precisely simulate the performance of human ears.

 The 60318-4 Occluded ear simulator was designed and specified to simulate the performance of a typical human ear in the frequency range from 100 Hz to 10.000 Hz. Modern acoustical wearables and listening devices are typically specified from 20 Hz to 20.000 Hz and therefore needs to be tested with ear simulators specified in this wider frequency range. This new proposal aims to cover the full frequency range of interest.