1. Finite Element Model of an Ear Simulator Pierre Gélat and Richard Barham 3 April 2003

2. Background  An ear simulator is a standardised device used for the calibration and characterisation of audiometers, earphones, and telecommunications and audio equipment.  Two types of ear simulator are widely used: the artificial ear standardised in IEC 60318-1 and the acoustic coupler standardised in IEC 60318-3.

3. Acoustic coupler and artificial ear

4. Description  The internal design of an artificial ear consists of three interconnected volumes to provide a complex impedance that mimics the nominal human ear  This is modelled using a lumped parameter approach, but its validity becomes questionable beyond a certain frequency.  A finite element model of the artificial ear has no such limitation. It can be used to: – validate the lumped parameter model – model the characteristics of the ear simulator at higher frequencies

5. Artificial Ear Diagram V 2 =1800 mm 3 V 3 =7500 mm 3 R1R1 L 2 R 2 L 3 R 3 Microphone V 1 =2500 mm 3  25mm

6. Axisymmetric model of artificial ear: pressure contours at 8 kHz

7. Conclusions  Poor agreement with lumped parameter model  Need to include viscosity effects  Working with PACSYS Ltd. to develop 1-D and 2-D viscous fluid finite elements