Non-resonant response using statistical energy analysis

When excited acoustically, the response of a panel consists of resonant and non-resonant waves. The non-resonant response is negligible for limp panels. However, it can become significant in the case of thin light structural panels. SEA modelling does not predict the non-resonant response of the structure. This paper discusses the above limitation of SEA and presents a modified SEA formulation by which the non-resonant response can also be estimated. The resonant and the non-resonant contributions to the response are assumed to be arising out of two separate subsystems. In the present formulation, modelling for non-resonant response is similar to the conventional SEA modelling for resonant response but uses different expressions for the coupling loss factors. The classical problem of two reverberant rooms separated by a panel is considered as an example. It is shown that by using this procedure the non-resonant response of the structure can be estimated. Also, the non-resonant sound transmission is obtained exactly. Results of a numerical example are presented to compare the conventional and the modified SEA modelling results.