Specifying the acoustic field in rooms in the low frequency range

摘要

In both the fields of noise control and sound transmission, determining the sound pressure in a given room continues to be an important issue. This is commonly done using a single value for each frequency band, and relies on the assumption that the sound field is sufficiently diffuse. For most room sizes and frequency ranges used this assumption is normally valid. However, this is not so for the lower frequency bands, especially as consideration now extends to frequencies lower than previously considered. In these lower frequency bands, the acoustic field cannot be considered to be diffuse, and other procedures need to be developed to reliably determine the sound field. This would imply much more complex measurement procedures, however one option is to change the definition of the parameters measured so as to minimize the effects of the lack of the diffusivity of the sound field. In the work presented, the effect of the spatial sampling of the sound pressure field and the definition of the bandwidths of the frequency ranges are investigated in order to assess new definitions of measurement that reduce the variability. This will lead to measurements that are more robust, repeatable and reproducible.