Comparação entre o Método do Tubo de Impedância e o Método In Situ sem a utilização de fonte sonora para a medição do coeficiente de absorção sonora

Abstract

It is important to know the sound absorption coefficient to allow the best choice of materials to given applications, as room coverings, for noise attenuation. There are three experimental methods for the measurement of the sound absorption coefficient: the Reverberant Chamber, the Impedance Tube and the In Situ Method. Currently only the Reverberant Chamber and the Impedance Tube have international rules of standartization, however the In Situ Method involves reduced costs in comparison to the others and permit the analysis of the acoustic properties of the materials at the place of use. This work presents a comparison of the results of measurements of the sound absorption coefficient using the Impedance Tube and the In Situ Method, in order to validate the use of the presented In Situ Method. The results show similar general behaviors in the sound absorption coefficients measured with the Impedance Tube and the In Situ Method. The global result indicates that the In Situ Method is an valid alternative to the sound absorption coefficient measurement, however it needs further development so it can generate satisfying results in its measures.