Abstract
The compound panel that is consists of some layers which have similar flexibility and adhered completely one by one, should be osscilated as one layer by incident sound wave in a phase as well as a layer which is made of a appropriate material. In this report, the frequency characteristics of sound transmission loss (TL) of some building panels which osscilate as one layer, are shown experimentaly and are discussed theoretically. As the result, their property of TL is able to presume by theoretical Mass Law, except for the frequency region where the coincidence effect is to be occured. The critical frequency of coincidence effect is governed by the rigidity of the layer and flequently the decrease of TL by the effect wonld be its fatal weak point of sound insulation. Then in this report, some nomographs to calculate the rigidity of typical panels which osscilate as one layer (Fig. -is for waved panel and Fig.-, -are for compound panel) are projected and their utilization is inspected by compareing with measured characteristic of TL.
