Human hearing at low frequencies

As a supplement to the current research within low frequency noise problems (see the projects "Annoyance of Low Frequency Noise", "Low Frequency Noise and Infrasound from Local Production Plants for Electricity", and "Explanations of Annoyance from Low Frequency Noise at Very Low Levels") a comprehensive literature review was carried out in order to collect the available knowledge about the human hearing at low frequencies (defined as frequencies below 200 Hz). The project comprised collecting of all available data from studies of hearing thresholds and equal-loudness-level contours for frequencies below 200 Hz. There is no standardized threshold for the infrasonic region (frequencies below 20 Hz), but on basis of the collected data a reliable hearing threshold has been calculated for this frequency region (using regression). A collection was also made of information about which factors that can influence the sensitivity of the ear, for example age, gender, exposure conditions etc. Furthermore, examples and possible explanations have been found on individual differences in the sensitivity of the ear that might explain how some people apparently can be annoyed by sounds that are not heard by others (see the project "Explanations of Annoyance from Low Frequency Noise at Very Low Levels"). Upon request, a review article was produced to a special issue on low-frequency noise of the international journal "Noise and Health" (see the linked publication). Supported by STVF/FTP.