Influence of TCAPS on HRTFs and on sound source localization precision
* Presenting author
The individual geometry of the auricle attenuates, resp. boosts certain frequencies of the incoming sound, depending on the angle of incidence. This effect is describe by the angle and frequency dependent HRTF, which is individual for each human and is not necessarily left-right symmetric. The brain is trained to the individual HRTF during a human’s lifetime. Wearing tactical communication and protection systems (TCAPS) modifies the geometry of the pinna, resulting in important changes of the HRTF. The listener’s brain cannot adapt instantaneously to the modified HRTF, leading to a less precise sound source localization. In listening test was obtained that the major type of error is due to front-back confusions. To pave the way towards TCAPS which preserve the listener’s natural spectral cues, three different models of TCAPS were analysed. Their influence on sound source localisation capabilities and on the user’s HRTF are presented. HRTF measurements on a dummy head were done during four scenarios: dummy head without TCAPS, dummy head wearing two different in-ear TCAPS (earplugs) and one on-ear TCAPS (earmuffs). Sound source localization tests were conducted with subjects under the same four scenarios. Based on those results concepts for prototype of new generation TCAPS are presented.