A simple low-invasive method to assess sound pressure levels at the eardrum using dual-microphone measurements in the open or occluded ear

performed using measurement techniques such as sound level meters (SLM) combined with estimated of exposure time or the use of portable noise dosimeters (PND). SLM and PND-based approaches only provide information about the ambient noise levels and fail to account for wearer's placement effects and inter-individual differences in the wearers' morphologies (e.g. head and ear geometries). While the damage risk criteria of existing noise standards refer to free-field measurements, it is commonly accepted that the risk of hearing loss is more directly related to the levels at the tympanic membrane. In-ear noise dosimetry (IEND) is a promising approach that provides continuous monitoring of an individual's noise exposure directly inside the ear. However, current IEND systems do not allow direct collection of eardrum data, as their featuring in-ear microphone is typically maintained at a certain distance from the membrane. This paper presents a simple method aimed at converting the measured SPLs to the eardrum, thus forming the basis for individual in-situ calibration of IEND. The method, based on a dual-microphone approach, and prototypes developed to conduct improved IEND measurements in the open or occluded ear are presented.