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A Mobile App for Geolocalized, Dynamic Binaural Synthesis

Hädrich, Markus; Lindau, Alexander; Weinzierl, Stefan

FG Audiokommunikation

Today, technical evolution and dissemination of smartphones have reached a point where powerful mobile computing has become virtually ubiquitous. Additionally, devices are equipped with a multitude of sensors and interfaces allowing for a – potentially continuous – acquisition of optical and acoustical data, the continued determination of bearing and position, and mobile network connectivity. Therefore, smartphones are increasingly used as a platform for mobile augmented or virtual reality applications. As a result, we report here on the development of an augmented audio application featuring Dynamic Binaural Synthesis (DBS) on iOS devices. The purpose of the app is to interactively render singular sound sources – sound spots virtually attached to fixed geographical positions – binaurally via headphones, while (currently) using the smartphone’s sensors to indicate the user’s viewing direction. With the help of a 2D map view, users may place multiple such sound spots in the actual (outdoor) environment - this way, for instance, creating augmented reality soundwalks. A proximity criterion is used to automatically switch the audio rendering process between different sound spots. During the realization of this application, special emphasis has been placed on finding suitable trade-offs between both a still cost-effective and plausible acoustic simulation. Thereby, obtaining an accurate continuous geographical position has emerged as a challenge.