Sound insulation and soundproofing. Comparison of weighted normalized apparent sound reduction index R'w and weighted standardized level difference DnT,w
In the German standard DIN 4109, sound insulation, expressed by the characteristic quantity ”R'w“, is used to indicate soundproofing. However, sound insulation and soundproofing describe different facts. Sound insulation indicates a quality of a separating element as ”resistance“ with the characteristic quantity ”sound reduction index, R“ and soundproofing describes a quality of protection between two rooms against sound transmissions and is expressed by the characteristic quantity ”level difference, D“. By comparing the two measures, it becomes clear that there must be a ”difference“ that can be represented not only algebraically in the equations. If the same rooms are examined objectively and subjectively, differences can be seen in both the number indication and the perception. In particular, it has been shown that the the rated normalized apparent sound reduction index (R'w) is assessed inconsistently in subjective terms, whereas the rated standardized level difference (DnT,w) shows a strong ”correlation“.