Uncertainty in sound diffusion and scattering coefficients measurement
Regular paper
AGH University of Science and Technology
Monday 1 june, 2015, 15:00 - 15:20
0.9 Athens (118)
Abstract:
Sound diffusers are characterized by two main parameters, that describe the
quality of the sound reflected from them. In the case of sound scattering
coefficient, which is measured in reverberation chamber according to ISO
17497-1 standard, it is recommend to calculate the uncertainty according to
the law of propagation. Only type A evaluation basing on measurement results
is presented, assuming, that input values are independent, hence it omits the
estimated covariance calculation.
In the paper the method proposed by the standard is compared with values
obtained taking into account correlation between input values and the results
of the Monte Carlo method. It was shown that for some frequencies, the ISO
standard uncertainty is much smaller, than calculated using other methods.
Authors analyzed also factors affecting uncertainty in measurement diffusion
coefficient, taking into account geometry of the measurement stand. Comparing
the influence of the position changes of the sample obtained for different
diffusers, uncertainty of the method was calculated depending on selected
parameters.