How to present pure-tone infrasound to the ear
* Presenting author
An increasing number of individuals are being exposed to infrasound. It is, however, still not clear, how infrasound is perceived by human beings. Regarding auditory perception, one hypothesis is that non-linear processes within the ear generate distortion products that make infrasound audible. To investigate this hypothesis, it is crucial to rule out that such distortions were produced technically, i.e., by the stimulus presentation system rather than the auditory system. This paper introduces a compact, low-distortion infrasound system, based on a commercially available audiometric earphone, for simultaneous presentation of pure-tone infrasound and audio sound to the ear via an ear insert. This system also allows for the recording of sound in the ear canal during signal presentation. Performance characteristics of the system for the stimulus presentation and the sound recording units are presented. It is shown that the interaction of infrasound and audio sound, such as modulation of the audio sound by the infrasound, is negligible with respect to auditory perception.