Fels, J. | Search bioRxiv

bioRxiv2020

Experiments on localization accuracy with non-individual and individual HRTFs comparing static and dynamic reproduction methods

Binaural reproduction can be used in listening experiments under real-life conditions to achieve a high realism and good reproducibility. In recent years a clear trend to more individual reproduction can be observed as the ability to measure individual head-related-transfer-functions (HRTFs) is becoming more widespread. The question of the accuracy and reproduction methods needed for a realistic playback however has not been sufficiently answered. To evaluate an appropriate approach for binaural reproduction via headphones different head-related-transfer-functions (HRTFs) and reproduction methods were compared in this paper. In a listening test eleven explicitly trained participants were asked to localize eleven sound sources positioned in the right hemisphere using the proximal pointing method. Binaural stimuli based on individually measured HRTFs were compared to those of an artificial head in a static reproduction of stimuli and in three dynamic reproduction methods of different resolutions (5{degrees}, 2.5{degrees} and 1{degrees}). Unsigned errors in azimuth and elevation as well as front-back-confusions and in-head-localization were observed. Dynamic reproduction of any resolution applied turned out fundamental for a reduction of undesired front-back-confusions and in-head-localization. Individually measured HRTFs showed a smaller effect on localization accuracy compared to the influence of dynamic sound reproduction. They were mainly observed to reduce the front-back-confusion rate.

neuroscience↗

bioRxiv2019

MobiLab - A Mobile Laboratory for On-Site Listening Experiments in Virtual Acoustic Environments

Research in the last decades has pointed out negative effects of noise on cognitive processing and general health. Depending on the frequency and level of exposure as well as individual shielding potential, risk groups like children or elderly people may be particularly vulnerable to commonly known consequences including a reduced attention span, influencing the learning success during education, increased blood pressure and cardiovascular problems or sleep disturbances. To better understand the susceptibility to noise, specifically designed listening experiments in controlled laboratory environments are indispensable but might put high demands on older study participants whose travel expenses to test locations could increase due to reduced mobility. For children, organizational issues like insured transport and supervision during waiting periods, necessitating additional resources, need to be resolved. In order to facilitate practical and efficient study execution, we therefore implemented a mobile hearing laboratory by acoustically optimizing the interior of a caravan. All necessary technical facilities were integrated to perform listening experiments in virtual acoustic environments under controlled conditions directly on site, for example, in front of schools or senior residential centers. The design and construction of this laboratory are presented here and evaluated through acoustic measurements.

neuroscience↗