Determination of Sound Reduction Index by impulse response measurements

The Sound Reduction Index of a partition can be measured according to the method described by ISO 140. This paper reports experimental results obtained with a new measurement method based on the determination of the impulse response in two rooms separated by the partition. In fact, it is possible to show that, by evaluating the Schroeder integral plot, we can calculate energy levels and reverberation time. The Sound Reduction Index is then calculated by using the relationship proposed by the ISO 140 series. The determination of the impulse response is made by using the exponential sine sweep signal excitation. These test signals guarantee high accuracy and repeatability in levels and reverberation time measurements. In this paper, the advantages and the drawbacks of the new technique will be discussed and the comparison with the traditional technique will also be shown.