When measuring the absorption coeficient of acoustic materials in a reverberation room a lot of changing parameters can cause considerable errors in all dtrerent frequency bands of interest. Although the ISOstandard, 'Measurement of the sound absorption in a reverberant room', spectfies the most essential details to increase the accuracy of the measurement results, important diflerences yet occur in repeatability and reproducibility measurements of the absorption coeficient. This paper describes the measurement of the absorption coeficient of direrent types of absorbing materials with total dtxerent absorption performances, taking into account the influence of equipment control, source and microphone positions, d@iers versus diffusity, the position of the absorbing material within the room, and the change in configuration of the reverberation room.
Although values of the absorption coeficient have been systematically evaluated with Sabine's and Eyring's formula, the presented results and comparisons are obtained from Sabine 's equation.