A comparative study of perceptional quality between wavefield synthesis and multipole-matched rendering for spatial audio

This paper introduces a new algorithm to render virtual sound sources with spatial properties in immersive environments. The algorithm, referred to as Multipole-Matched Rendering, uses the Method-of-Moments and Singular-Value Decomposition to optimally match a spherical-multipole expansion of the virtual source to the field resulting from a spatially distributed speaker set. The flexibility of this method over other approaches, such as Wavefield Synthesis, allows for complex speaker geometries, and requires a smaller number of speakers to achieve a similar spatial rendering performance for listeners in immersive environments. The trade-off for the enhanced performance is a smaller area of faithful reproduction. This limited area, however, can be focused around listener locations for a sweet-spot solution. Experimental results are presented from perceptual tests comparing Multipole-Matched Rendering to both Wavefield Synthesis and stereo rendering using a linear speaker array. The experiments included 13 subjects and demonstrated that the perceived direction of a virtual sound source for the new method is comparable to that of Wavefield Synthesis (no significant difference). The results demonstrate the potential of Multipole-Matched Rendering as an efficient technique for rendering virtual sound sources in immersive environments.