Abstract
Double-leaf sound insulating wall is widely applied to cabins of air-plane or high-speed train, because transmission loss is larger nevertheless the weight is light. But transmission loss of double-leaf is decreased at the resonant frequency of the wall. So we tested tuned mass dampers and tuned mass dampers with damping to increase transmission loss at the resonant frequency. And we observed vibration modes of the surface of the wall and measured the transmission loss. Those results show that vibration modes which are generated by tuned mass damper and tuned mass damper with damping affect the sound transmission loss.
