Impulse noise attenuation by earplugs measured with the use of an acoustical test fixture and with the participation of subjects

Abstract

The effectiveness of impulse noise attenuation by hearing protector devices is most often determined collecting the data from measurements. In impulse noise conditions with high peak sound pressure level it is necessary to replace a subject in a measurement with an acoustical test fixture. The use of the acoustical test fixture is important because of the potential risk of hearing damage occurring during impulse noise tests, performed with the participation of subjects. The impulse noise attenuation by earplugs determined from measurements carried out using acoustical test fixture was compared with attenuation determined with the participation of subjects (MIRE technique). The acoustical test fixture complied with the acoustic and mechanical requirements described in Standard No. ISO 4869-3 and was equipped with a chamber representing the external ear canal and a 2 cm3 chamber reflecting the acoustic properties of the middle ear. The results of measurements carried out with two different methods were comparable.