Perception of Acoustical Spatial Attributes and Impression in Virtually Rendered Sound Field

Computation power to simulate sound fields from the three-dimensional numerical models has progressed fast; for example, using GPU cluster systems. We can render directivity, position , distance, and reverberation of sound sources in a practical time. Furthermore, a multi-channel sound field system can be realized with low-cost digital-to-analog converter modules. Moreover, some researchers are trying to implement sound field techniques with over-hundred-channel loudspeaker arrays. However, the intervals among loudspeakers used in reproduction of the rendered sound field are insufficient to avoid spatial aliasing. Therefore, it is impossible to reproduce the rendered sound field accurately with current loudspeaker systems. Nevertheless, subjective impression of reproduction field with an insufficient system might be similar to intended sound field. The intended spatial attributes to render, such as sound position, sound directivity, reverberation, should be evaluated subjectively. In this presentation, we performed a subjective evaluation of the sound fields rendered with a graphical processing unit (GPU) cluster. The sound fields were reproduced by a surrounding loudspeaker array or by binaural system. First, we perform an experiment with the surrounding loudspeaker array. The number of loudspeakers in the array was 157. However the distance among loudspeakers was 50 cm and was insufficient to reproduce frequencies higher than 340 Hz. Listeners answered their subjective impressions on distance and directivity of sound source of a singing voice. We confirmed listeners could perceive the rendered distances in part when the directivity of the sound source was also rendered. Next, we investi-The 22 nd gated whether it's possible to discriminate sound fields, which are different in upper-limit frequency of the spatial aliasing with virtual environments with the binaural system. As a result , listeners cannot discriminate the sound fields over 4 kHz. These results are valuable to transmit spatial information with a practical system.