Design Principles of the Italian Round Robin Test on Reverberation Rooms

This paper describes the design principles underlying the Round Robin Test (RRT) carried out among the laboratories of the Sound Absorption working group of the Italian Standardization Body (UNI). In recent years, the determination of the measurement uncertainties in the fields of building and room acoustics has attracted increasing attention. In particular, sound absorption in a diffuse sound field has always been difficult to determine, especially for very highly absorptive materials, e.g. due to the edge effect; results coming from different laboratories cannot always be compared, due to differences in the actual sound field found in nominally equivalent facilities. During this RRT, carefully selected samples have been measured in the reverberation rooms of the different laboratories participating in the RRT according to the published ISO 354 standard as well as the newly proposed draft. The procedure will be presented in the paper.