Speaker
Description
Perception of everyday sounds typically involves motion of the source and receiver, sound reflections, diffraction, and reverberation. Contrasting classical psychoacoustics with static headphone rendering of simplified stimuli, hearing research in such realistic conditions requires virtual acoustics methods. liveRAZR is a low-latency interactive virtual environment and room acoustics simulator designed for auralization in dynamic environments with full six degrees of freedom (6-DoF) motion for both sources and listeners. It employs geometric acoustics (GA) techniques, including image-source modeling for early reflections, combined with computationally efficient late-reverberation modelling to achieve perceptually plausible and physics-driven results under real-time constraints. To address limitations of purely specular GA propagation models, liveRAZR incorporates edge diffraction modeling. This allows the simulation of sound propagation into shadowed regions and around obstacles, improving realism in complex scenes with partial occlusion. Diffraction paths are evaluated efficiently to remain compatible with interactive performance requirements. The system supports binaural rendering using measured high-resolution head-related impulse responses and integrates source directivity datasets via SOFA files. Directional filtering is applied through partitioned convolution, enabling accurate reproduction of spatial cues during listener and source movement. Implemented as a multi-threaded C++ application, liveRAZR can operate standalone or be controlled externally via OSC messages from a controller application such as, e.g., Unreal Engine. This architecture supports continuous updates of scene geometry and listener state. We discuss the psychoacoustically relevant key features of the suggested system and present use cases involving auditory distance perception, exemplifying how psychoacoustics can be performed in realistic, yet lab-controlled and reproducible conditions, approaching natural behavior and perception of everyday sounds.