When octave bands are not enough: Case histories of indoor room noise

All of the published indoor noise criteria evaluation methods are defined on the basis of either the octave band or the overall A- or C-weighted sound pressure levels. While this may be sufficient for some acoustic environments, there are many situations where these sound level descriptors are totally inadequate. This paper uses case histories to show that 1/3-octave and narrow-band analysis is sometimes required to properly assess the acoustic environment. To take it one step further, a recommendation is made to avoid the use of octave bands altogether and to routinely use 1/3-octave band analysis for acoustical measurements and analysis relating to indoor noise criteria.