Technical Note: Prediction Models of Airborne Sound Insulation of Multilayer Materials with Viscoelastic Thin Sheets

The growing introduction of new insulation materials in building acoustics has caused an increase of the importance of the prediction tools. Appropriate simulations allow strictly necessary laboratory measurements to be identified. In this way, costs are reduced. The demands of new legislation has resulted in the appearance of various software designed to facilitate prediction. The prediction models are based on different hypotheses: adaptation of impedances, spatial behaviour of spectral components, statistical energy distribution, the Finite Element Method (FEM), etc. Each of these models and methods offer advantages and contain limitations. In this paper, different models for prediction of sound insulation of multi-layer systems, are analysed. A method, based on adaptation of impedances is considered, and the results are compared with those obtained from FEM and also from experimental results. Adjustments are proposed to the models, to improve the prediction in certain frequency ranges.