AN INVESTIGATION OF THE RELATIONSHIPS BETWEEN THE ATTENUATION OF EARPLUGS AND EARMUFFS WITH INCIDENT SOUND LEVEL FOR STEADY-STATE AND IMPULSE SOUNDS USING INSTRUMENTED CADAVER EARS

摘要

The linearity of attenuation with incident sound level of four types of earplug and four types of earmuff has been investigated using freshly prepared and instrumented cadaver ears. Pure tones and /3-octave bands of random noise in the frequency range 125 to 8000 Hz were employed as steady-state stimuli with sound pressure levels between 75 and 125 dB. Impulses having peak sound levels in the range 135 to 175 dB(p) were also presented. Attenuations were determined in terms of transmission loss and insertion loss, although only the latter parameter was used for comparison with results from other measurement procedures.