Effects of characteristics of noise on the perception and propagation of bone-conducted speech with earplugs

Abstract Bone conduction (BC) transmits sound through living tissue, which allows some components to reach the inner ear directly. Therefore, BC sound can be heard even with earplugs. BC has been applied to voice communication devices in environments with extreme noise to protect the ears. However, the perception of BC sound under such conditions varies with multiple factors, including noise characteristics. We investigated the effects of exposure to noise on the perception of BC speech with earplugs from psychological (intelligibility test) and bioacoustic [ear-canal sound pressure (ECSP) and head vibration measurement] perspectives. White, pink, and Japanese babble noises were used in the experiments. Intelligibility was highest with babble noise and lowest with white noise, which suggests that intelligibility deteriorated more with noise containing more high-frequency components. Although the ECSP measurements corroborated the findings of the intelligibility tests, the measured head vibration values were not affected by exposure to noise.