Reverberation Times Obtained Using a Numerical Model Versus Those Given by Simplified Formulas and Measurements

摘要

This paper describes a set of analytical solutions used to evaluate the pressure response inside an empty parallelepiped closed space subjected to a harmonic point source. The model allows different absorption coefficients to be defined for the various walls, as well as frequency variation. The computations are first performed in the frequency domain and Inverse Fourier Transforms are subsequently applied to obtain impulse responses. The time-aliasing phenomenon is avoided by using complex frequencies to attenuate the response at the end of the time frame. This effect is later taken into account by re-scaling the response in the time domain. The model developed was applied to different scenarios for which reverberation times were computed using the Schroeder approach. Pulses with varying characteristic frequencies were modeled so that the influence of the excitation frequency on the reverberation times could be studied. These results were then compared with those provided by the simplified models of Sabine, Eyring, Millington, Fitzroy and Arau-Puchades. Experimental measurements in situ were also compared with those provided by the numerical model.