Abstract
The effect of sound scattering objects in a rectangular room with high absorption at the ceiling and low absorption at the walls and floor was investigated. In Part I of this paper a two-system Statistical Energy Analysis (SEA) model was developed in order to predict the gross features of the decay process. The sound field is subdivided into a grazing and nongrazing part. The main effect of introducing irregularities is to divert some of the energy in the grazing group into the nongrazing group. The energy transfer between the groups is taken into account by introducing a coupling loss factor. In order to quantify the effect of scattering objects and other irregularities, a measure called equivalent scattering area is introduced. The model demonstrates how the equivalent scattering area can be determined from measurements.