Verification of using SEA to model differing laboratory conditions

Abstract

In the Inter-comparison of European Laboratory Measurements of Airborne Sound Insulation of Walls under the EC Measurement and Testing Programme 1990–1994 a significant difference, of up to 12 dB, was found in the reproducibility results for the participating 21 laboratories. This difference was associated only with specimen 1, the double leaf lightweight plasterboard wall. This paper presents possible reasons for the large reproducibility values for this wall using experimental evidence and theoretical models, statistical energy analysis (SEA). While the calculation of the sound reduction index (R) does take into account the different test wall areas and reverberation times of the respective laboratories involved, some factors which may prove significant to the measured R values are not. This paper discusses a variety of factors which may affect the resultant R values. It is suggested that the principle factor which may effect the results of this test program for the double wall is the material used for the border of the test opening in the various laboratories, which connects both leaves of the double wall. The SEA can be used to model approximately the various laboratory conditions. When comparing the measured and SEA predicted reproducibility results there is good agreement.