One-Eartip Solution for Pure-Tone Audiometry & Acoustic Immittance Measurements: Using Insert Earphone with an Immittance Probe Ear Tip

Two consecutive studies sought to determine the (1) audiometric calibration levels (ETSPLs) and, (2) real ear attenuation thresholds (REAT) for the KUDUwave earcup used with an insert earphone using a typical immittance probe tip (TPT).

In study one (1), hearing thresholds were measured for frequencies 125 - 8000 Hz using the TPT. Equivalent Threshold Sound Pressure Levels (ETSPLs) were calculated in an IEC 60318-4 occluded ear simulator. In study two (2) REAT were obtained by measuring sound field thresholds with ears uncovered and covered with the investigational transducer. The attenuation values were used to determine the maximum permissible ambient noise levels (MPANLs).

The determined TPT ETSPLs differed from the ER-3A foam-tip insert earphone’s RETSPLs reported in ISO 389-2. The attenuation values were high enough to test down to 0 dB HL.

The investigational transducer can be used for pure-tone audiometry provided the reported MPANLs are adhered to, and ETSPL values are employed for calibration purposes. The advantage is to achieve a cost-effective, one-probe tip solution for pure-tone audiometry and immittance measurement.