Listen carefully: Volume adjustment behavior for portable music player usage with headphones

Sound exposure is one of the primary causes of preventable hearing loss. Traditionally, sound exposure has been associated to industrial settings, and as such, treated as an occupational safety issue leading to international standards regulating sound exposure to improve working conditions. High levels of sound exposures are experienced in modern society in many different situations such as attending concerts, sport events and others. This leads to an interest in measurement devices which are discreet and simple to use, in order to assess sound exposures encountered in typical daily life scenarios. The purpose of this work is to document the use of a modified behind-the-ear (BTE) hearing-aid as a portable sound pressure level (SPL) meter. In order to obtain sound level measurements with a BTE device comparable to sound field values that can be used with existing risk assessment strategies, differences due to microphone positions and the presence of a person in the measurement must be taken into account. The present study presents measurements carried out to document the characteristics of the BTE device, using the same framework presented in the ISO 11904 standard series. The responses at the BTE position on a head and torso simulator (HATS) were measured and combined with the A-weighting filter, frequency weigted sound field values. The compensation filters improved the accuracy of the BTE devices especially in laboratory conditions. Field tests corroborate the necessity of both diffuse- and free-field compensation devices showing better approximations for corresponding sound field scenarios.