Numerical Investigation of the Repeatability and Reproducibility of Laboratory Sound Insulation Measurements

Abstract

An extensive parametric study has been carried out with a wave based model to numerically investigate the fundamental repeatability and reproducibility of laboratory sound insulation measurements in the frequency range 50-200 Hz. Both the pressure method (according to ISO 10140-2) and the intensity method (according to ISO 15186-1 and ISO 15186-3) are investigated. The investigation includes the repeatability of the different measurement procedures, which depends on the influence of the microphone positions and the source position. The reproducibility of the sound insulation measurements in different test facilities is studied by looking at the influence of geometrical parameters like room and plate dimensions, aperture placement and aperture thickness. The results show that for small-sized test elements, the reproducibility of the intensity method is better. For heavy walls and lightweight double constructions, however, the predicted uncertainty is similar for the three measurement methods. The results of the reproducibility study are also used to investigate systematic differences between the pressure method and both