Abstract
Noise induced hearing loss (NIHS), the well-known occupational disease, is caused by continuous excessive noise. The prevention of NIHS is very important, because it is unrecoverable. There are some kinds of hearing protection device (HPD), and those are effective in preventing NIHS. But workers in noisy environment often resist to wearing them. Because they are ready - made products, so workers feel uncomfortable to wear. Also, they didn't maintain the conversation frequency range, so workers are hard to communicate in wearing them. To prevent hearing loss effectively, it is important that workers keep wearing HPD. Therefore, a HPD is needed to be comfortable to wear and be effective not only in hearing protection but also in preserving communication ability. So we proposed a custom - made hearing protection device in which a small acoustic filter is inserted. We designed several kinds of small acoustic filters and carried out some acoustic experiments for measuring characteristics of filters. We confirmed that acoustic transmission characteristic can be adjusted from experimental results using designed small acoustic filters. And we researched for the actual efficiency of a new developed custom - made hearing protection device using a small size acoustic filter. Also, we found out that workers are more satisfied with the new development than a former protection device from a workers' response.
