Abstract
The present paper presented the concept of, Sound Reduction Structure, in which hard sound absorbing materials are directly installed on the surface of vibrating solid body with some back air spaces. First, by the study assuming one-dimensional acoustic field, it was ascertained theoretically that the sound reduction effects are actually obtainable by the Structures with moderate back air space, showing the good agreements with the experimental results. Then, for the cases of vibrating rigid piston plates or flexible rectangular flat plates with vibrating modes, sound reduction characteristics in the three-dimensional acoustic fields were experimentally clarified in detail.
