Study on sound absorption characteristics of a sound absorbing wall with built-in resonators: investigation through experiments with full-scale model and analyses with boundary element method

In industrial plants and machine rooms, various types of noise are generated such as equipment noise. In this case, porous materials are often used for sound absorption. However, there are cases in which water and dust are generated in these places, which reduces the sound absorption performance of porous materials. Furthermore, a thick air layer is required behind porous materials to absorb low-frequency sounds such as equipment noise. This reduces the working space and complicates construction of fixing porous materials. For these reasons, porous materials are often difficult to apply. Therefore, there is a need for a sound absorbing material that is thin and resistant to water and dust. To address this need, we are researching on a sound absorbing wall with built-in Helmholtz resonators in its interior space. This wall protects against water and dust with its surface and absorbs sound through resonance type sound absorption with resonators and the panel type sound absorption with the interior wall. In this report, we investigate the sound absorption characteristics of the sound absorbing wall using the results of experiments with a full-scale model and those of analyses with boundary element method (BEM).