Comparison of the Sound Transmission Variability with Published Results on Coupling Loss

Abstract

Whilst most predictions in building acoustics and design invariably use published and readily available models, some attempt to quantify confidence limits that cover most cases would be invaluable. For instance, the parameters (e.g. room dimensions, panel position, room absorption, etc.) are shown to have a substantial effect on Noise Reduction (NR) and Coupling Loss Factor (CLF), the latter being a very important factor for predicting sound transmission using Statistical Energy Analysis (SEA). A Statistical Energy Analysis (SEA) model was implemented and used herein for the prediction of CLFs between two rooms. Thus, the main goal this research is to make an initial parametric investigation for the Coupling Loss Factors (CLFs) and then compare their variability with theoretical upper and lower bound curves previously presented in the literature for structure coupling. The usefulness of SEA as a framework of analysis can be assessed by the estimation of variance and confidence intervals. In addition, the spatial-average mean square sound pressure for each SEA subsystem was estimated via a Component Mode Synthesis (CMS) model developed in a previous paper. In summary, the room acoustic pressures were obtained via a CMS procedure and subsequently used in a SEA model where the equivalent CLFs were evaluated on basis of SEA assumptions. The influence of other SEA parameters, such as modal density and modal overlap was also considered.