Keyword:
Single-number values of sound absorption

So-called "single values" are used to simplify the representation of the frequency-dependent sound absorption coefficient and to make a rough comparison of different sound absorbers. In Europe, the "rated sound absorption coefficient" αw according to DIN EN ISO 11654 is commonly used. Single values commonly used in the US are the NRC and SAA values. All of the values mentioned are based on measurements of sound absorption in third octaves or octaves. For detailed room acoustic planning, precise knowledge of these sound absorption values in third octaves or at least in octaves is required (see "Octaves").