Neubauer R.

The airborne sound insulation between dwellings describes generally the quality of the indoor living environment. There is a general acknowledgement using the current standard method of predicting airborne sound insulation according to EN ISO 12354-1. In order to predict an increase of airborne sound insulation subjectively recognised as a sufficient improved sound insulation, it is known that the standard method is not suitable to predict psycho-acoustical parameters such as loudness in an adequate way. One might be tempting to believe an increase in airborne sound insulation of a certain factor, leads also to a subjectively judged increase of noise prevention of the same factor. However, in some sound insulation requirements described e.g. in the German Standard DIN 4109 a raised weighted sound reduction index of one and two decibels is supposed to indicate an increased sound insulation. The question arises, is this a better sound insulation, indeed? The question whether an airborne sound insulation is judged as sufficient or not can not be answered in a simple way. After the transformation from the sound descriptor into a hearing descriptor such as loudness, it might be possible to predict an increasing sound insulation in a more realistic manner. This research work was therefore primarily focused on the question how much has the sound insulation to be increased to make subjectively a difference. For this reason pink noise was used as noise source replacing a raised spoken voice. The sound insulation used in this investigation, which included two different structures, i.e. a heavy and a light weight construction, are calculated according to EN ISO 12354-1. The sound level in the receiving room was calculated. The computed results were loudness and loudness level, which were more appropriate values indicating subjectively judged increase of different air borne sound insulation depending on background noise level.