Numerical estimation of coupling loss factors in building acoustics

A study on the optimal procedure for obtaining SEA (statistical energy analysis) coupling loss factors (CLF) numerically is presented. The energies of an SEA system with two subsystems (one excited, the other one unexcited) are obtained from deterministic numerical simulations. Three different ways of isolating the CLF are explored: from the power balance of the excited subsystem (first approach) or the unexcited subsystem (second approach) and from the power transmitted through the connection (third approach). An error propagation analysis shows that the first approach is unreliable and that the second approach is the best option. As application examples, the CLF between some typical building structures is computed. These examples illustrate the potential of the estimated CLFs to solve larger problems with SEA and show the influence of the type of excitation on the coupling loss factor estimation. Finally, a simplified technique to account for the effect of studs in double walls with SEA is presented.