Effects of ear canal occlusion and masking on the perception of voice.

This study examined the effect of ear canal occlusion and masking noise on four parameters of voice: (1) average fundamental frequency, (2) intensity in decibel (dB), (3) maximum fundamental frequency observed in a given sample (max), and (4) minimum fundamental frequency observed in a given sample (min). 12 normal hearing undergraduates produced the vowel /i/ ten times under conditions of unoccluded ear canal, ear canal occluded with a sound attenuating earplug, or masking noise. Other than a small (.73 dB) decrease in intensity, analysis showed no significant changes under the occluded condition; however, the masking condition showed statistically significant increases in the fundamental frequency, the intensity, and the maximum and minimum frequency as well as an increased range of frequencies.