Interactive rendering of dynamic virtual audio-visual environments for "subject-in-the-loop" experiments

• Published in: The Journal of the Acoustical Society of America Vol. 146; no. 4; p. 2801
• Main Authors: Grimm, Giso, Hendrikse, Maartje M., Hohmann, Volker
• Format: Journal Article
• Language: English; Japanese
• Published: 01.10.2019
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.5136702

The benefit from hearing devices with directional filtering algorithms, e.g., hearing aids with fixed beamformers, may depend on the user’s head movement behavior. Traditional evaluation methods for hearing devices often do not allow for head movements, or present stimuli in tasks which do not result in natural movement behavior of the participants. To overcome these limitations, virtual audio-visual environments are increasingly used to reproduce listening environments. Here, we present a software tool for interactive real-time simulation of audio-visual virtual environments. Simulation methods for time-domain rendering of direct sounds and early reflections in a geometric image source model in combination with a simple method of rendering diffuse sound fields from first-order Ambisonics recordings as well as diffuse reverberation from recorded first-order Ambisonics impulse responses are presented. A set of five typical and difficult listening environments was created in the lab with loudspeaker reproduction, and the movement behavior of 40 young and elderly normal hearing listeners was recorded in these environments. Furthermore, the influence of this individual head movement data on the performance of various signal enhancement algorithms was simulated. Data show that the application of virtual acoustic environments may contribute to a higher ecological validity of lab-based hearing-device evaluation methods.