Three-dimensional remote ensemble system using the immersive auditory display “Sound Cask.”

A 3D sound field simulation system using the immersive auditory display system, “sound cask,” has been developed for creating a virtual environment that would reproduce the 3D acoustics of concert halls for musicians. The simulation system is based on the boundary surface control principle. The original sound field was measured using a microphone array consisting of 80 omnidirectional microphones installed at the nodes of the C80 fullerene structure. The virtual sound field was then constructed in a cask-shaped space (approx. 2 × 2 m), with 96 channel full-range loudspeakers installed in the space. The 3D acoustic waves of music, including the acoustic condition on the stage, were created virtually inside the sound cask. For this, the first step was to design inverse filters of the MIMO system between the 96 loudspeakers and 80 microphones located in the sound cask. Next, the inverse filters and the impulse responses measured in actual concert halls and signals from instruments played by musicians were convolved in real time. Using two sound casks connected each other, three-dimensional remote ensemble system can be realized. Room acoustic indices between the actual and virtual conditions were compared, and subjective experiments involving professional musicians were performed.