Performance Studies on a New Artificial Ear

Component values of an eight-element electrical network analogue which simulates the acoustical impedance of the average human ear have been agreed as provisional design parameters for an I.E.C. artificial ear. A device which conforms to these parameters has been previously described by the authors and this paper compares its performance in calibrating different types of audiometric earphone with direct subjective calibrations. Over a wide frequency range it is superior to artificial ears and couplers in general use and the new device also reproduces the real ear threshold sound pressure level. However, the principal advantage is that at any frequency a single value of equivalent threshold sound pressure level, independent of earphone type, can now be specified and values have been derived which are compatible with current I.S.O. Recommendations.