Comparison of two methods for in-situ measurement of the absorption coefficient

摘要

The Adrienne method is an often used measurement technique developed for outdoor (in-situ) measurements of sound reflection and airborne sound insulation, as standardized in the CEN/TS 1793-5 norm. This norm was used as the basis for the design of two measuring systems for determining the absorption coefficient and sound insulation of noise barriers and built-in roof and wall systems where no laboratory data on the acoustical performance are known. The goal of this paper is to compare both systems using the Adrienne method of in-situ measurement of the absorption coefficient and another method which uses multiplication of the impulse responses with the ratio between estimated time of arrival of the direct and reflected incoming sound impulse, as used in some commercial acoustic measurement applications such as Easera. The used excitation signal was the exponential sine sweep. The measurement results obtained by these two methods were analyzed, processed and the results are compared.