ARTIFICIAL EAR

Typical Number in Hospital: 1

Cost Bands: 2

References: 8

When testing the sound pressure level generated by an earphone a coupling device is required between the earphone and the microphone of the sound pressure level meter which will simulate the acoustic impedance (effective compliance) of the natural ear. This normally takes the form of a cavity with correct fittings at each end for the earphone and the microphone and has a volume roughly equivalent to the ear/earphone system. For a normal earphone this volume us usually 6 ml and a simple device (called a 6 cc coupler) may be used, and for an ear plug or ear mould 2 ml is required (2 cc coupler). Simple couplers do not accurately simulate the impedance of a real ear and a true artificial ear has additional cavities in order to create the more complex impedance characteristics of a real ear.

Artificial ears are used in the calibration of hearing aids or headphones on their own or as part of an audiometer.