Abstract
The authors have developed a noise reduction system to reduce the transmitted sound passing through panels by fixing noise insulation panels consisting of thin plates, piezoelectric materials and control circuits. In the case where an inductance circuit was used as a control circuit, the radiated sound reduced in narrow frequency range. In this paper, we have described a way to spread the frequency range of control by double layer noise insulation panels with piezoelectric material. By the experiment, it was possible to reduce transmitted sound in two bandwidths of frequency. However, the shift in the frequency of control was confirmed by comparing single layer with double layer.
