Effects of Unspecified Experimental Conditions in ISO 17497-1 on the Scattering Coefficients Measured in a Scale Model

This study extends the authors' previous investigation on the measurement of random-incidence scattering coefficients in a reverberation room [Acta Acustica United with Acustica 94 (2008) 769-773]. The present study further investigates the effects of some unspecified experimental conditions in ISO 17497-1 on the measured scattering coefficients; these conditions include the sample diameter, the addition of an edge strip around the sample perimeter, the air gap below the turntable, and the absorption of the test sample. The results of scale-model measurements indicate that the sample diameter, air gap below the turntable, and absorption of the test sample have significant effects on the measured scattering coefficient, particularly for values obtained in the mid- and high-frequency bands. The edge effect is minimized by using an edge strip around the sample perimeter; the edge strip has a considerable influence on the scattering coefficients in the highest frequency bands.