The importance of in-plane waves in sound transmission through buildings

Abstract The effect of including in-plane waves in a statistical energy analysis model of a building is examined. It is shown that the additional waves make little difference close to the source, but large differences can occur far from the source if they are omitted. It is found that there is close to equipartition of energy between longitudinal and transverse modes. This allows the model to be simplified by combining longitudinal and transverse subsystems into a single in-plane subsystem. Agreement between the measured and predicted response of a building was reasonable except where there was significant airborne sound transmission along corridors. There was some scatter of results but much of this can be explained by the effects of small random errors in the individual coupling loss factors which cannot be predicted.