AIRBORNE SOUND INSULATION BASED ON A MODEL OF LOUDNESS

An objective description of airborne sound insulation between rooms still challenges house builders as well as house owners. In order to describe the measure of the quality of sound protection, different descriptors are used in different countries. This paper introduces a calculation scheme based on loudness level linked with specific fluctuation strength, yielding a weighted normalised loudness level difference. By analysing the difference between standard airborne sound insulation values and the introduced weighted normalised loudness level difference, it is revealed that the sound pressure level which is transmitted through a partition decreases with increasing frequency, and this is independent of the type of signal and of the airborne sound insulation values (R’w-values), whereas if the transmitted signal is converted into a loudness level, it tends to rise with increasing frequency. Moreover, it is found that, while a simple level difference does not allow investigating a single frequency dip in an airborne sound insulation curve, using the weighted normalised loudness level difference a significant change can be observed. Furthermore, the frequency dependent results allow more details to be investigated for a certain sound insulation. In this paper it will be shown that an objective descriptor of airborne sound insulation based on psychoacoustic magnitudes like loudness level and specific fluctuation strength can largely account for different aspects, particularly if it is supposed to describe hearing sensation.