Subjective and objective evaluation of impact noise sources in wooden and heavyweight floor constructions

Buildings with wooden floor constructions and wooden prefabricated single family houses have a long tradition in Germany. From the middle of the 1990s, wooden multi-storey houses have been built in many European countries. In general, those multi-dwelling houses have to fulfil the same acoustic requirements as concrete buildings. Especially the requirements on impact noise can be difficult to achieve. Often, even when they are fulfilled, many complaints in wooden buildings are due to low frequency impact noise. The weighted normalized impact sound level does not take into account frequencies below 100 Hz, and the combination with the spectrum adaption term CI only considers frequencies down to 50 Hz. It is not clear if subjective judgements are influenced by frequencies below 50 Hz. Obviously the weighted normalized impact sound level does not correspond to subjective judgements. One of the reasons for this might be that the tapping machine, which is used for standardized measurements, has a different excitation characteristic than walking people and other real sources of impact noise, such as shifting chairs or falling objects etc. In the research project "AcuWood", the impact noise of wooden floor constructions is investigated. By measurements, listening tests and questionnaires it is intended to find descriptors for impact noise, which better correlate to the subjective evaluation.