Custom-molded earplugs (CMEPs) whose canal segments extend beyond the second bend of the ear canal can provide excellent attenuation but can sometimes be uncomfortable. Attenuation was measured for CMEPs whose canal segments were shortened in 2-mm increments. The within-subjects design permitted illustration of the form of the function relating attenuation to canal segment length for individual...

This work presents a new method for assessing the normal incidence insertion loss (IL) of earplug (EP) by the use of a classical impedance tube. The proposed technique allows for fast and straightforward IL measurements and thus is particularly suitable for earplug testing in a design phase. Indeed, compared to standard ATF measurements, the proposed method does not require cumbersome experimen...

Machines and equipment or work processes that make noise. Evaluation of noise intensity is carried out by making a map describes the distribution pattern from 278 measurement points then processed with surfer software, which becomes basic information to protect workers risk hearing loss. After measuring analyzing data, level ranged lowest 41.0 dBA, highest 101.9 dBA. From map, it can be seen ma...

SUBJECT PREPARATION The subject fills out a standard MRI questionnaire to be sure that they are not precluded from the MRI study due to existing medical conditions. Safety precautions (as indicated on the questionnaire, e.g. use of earplugs) are implemented. After giving informed consent, the subject lays supine on the MRI table, and the RF coil is placed around the subject’s head. Head motion ...

INTRODUCTION Noise levels from military aircraft range from 100-130 dBA. Peak pressure levels from large caliber weapons may reach 180 dB SPL. To protect against hearing loss, individuals are encouraged to wear double hearing protection. This study determined ways to maximize benefit. METHOD Hearing thresholds from 0.25-8 kHz and consonant discrimination were assessed in normal-hearing subjec...