Impulsive sound level response statistics in a reverberant enclosure

Abstract

An analytical model based on the experimental results presented in the preceeding paper has been developed which predicts the sound pressure level (SPL) exceedance probability distribution (EPD) of an enclosure to an impulsive noise source. The rms sound pressure is found by calculating the total energy per source impulse at the receiver. An energy partition method in conjunction with a method of images is used to calculate the total energy. Since a numerical or analytical calculation of the SPL EPD in a reverberant enclosure is not feasible, an equivalent 1 DOF system is predicted whose normalized EPD response is similar to that of the enclosure. The principal source parameters in the model are the impulse peak amplitude probability density, occurrence rate, and duration. The principal enclosure parameters are average sound absorption coefficient, volume to surface area ratio, shape, and location of barriers relative to the noise source and receiver, Generally, agreement between experimental and calculated results employing the model are very good. An example is included illustrating the use of such predicted responses in industrial noise applications. [Work supported by NSF Grant GK 4340.]