Twenty-two cases of low-frequency noise complaints: a detailed investigation

In Denmark and in other industrialized countries there are cases where people complain about annoying low-frequency or infrasonic noise in their homes. Besides noise annoyance people often report other adverse effects such as insomnia, headache, lack of concentration etc. In many cases the noise can only be heard by a single person in the household, and if measurements are performed the authorities cannot find any noise exceeding the existing limits for noise. This raises the fundamental question whether the complainants are annoyed by an external physical sound, or if other explanations must be sought. The main aim of this study is to answer this fundamental question by thoroughly investigating 22 such cases. Recordings and analyses were made of the sound in the complainants’ homes. Each complainant was then invited to the laboratory where low-frequency thresholds and equal-loudness contours were measured. In a blind test it was examined if they are able to hear the sound recorded in their homes. Details from noise recordings, analysis and the experimental design are presented, however, since the experiments were finishing at the time of paper submission no results are presented at the present stage, but the final results will be presented at the conference.