Acoustic Coupler and Measurements Designed for Newborn Hearing Tests

Acoustic coupler designed for newborn hearing assessments has been used in in vitro testing. The acoustic transfer impedance of the coupling was determined and compared with the theoretical model. In addition, its sensitivity to environmental conditions such as temperature and pressure at frequencies between 100 Hz and 10 kHz was investigated. Ear coupler was compared with IEC 60318-4 ear simulator and 2 cm3 coupler and the results were investigated. Uncertainty in calibration was calculated according to the methods outlined in "Guidelines for Expressing Uncertainty in Measurement (GUM, ISO, 2nd edition, 1995)" and EA-4/02 (EA, 1999). An error-based model function has been created for the uncertainty calculations in acoustic transfer impedance calculations and a detailed uncertainty budget has been given.