Discrimination of virtual sound fields different in spatial aliasing

There are theoretical techniques for sound field reproduction with a loudspeaker array. However, physical precision of synthesized sound field is limited in frequency domain. When the distance among loudspeakers is below a half of wavelength, spatial aliasing will occur. The ideal distance among loudspeakers was less than 8.5 mm@20 kHz, and it is impossible to arrange loudspeakers. Therefore, we carried out experiments to know an upper-limit frequency condition, which can give subjective experience identical to an ideal sound field. We assumed a virtual spherical boundary around a listener. Numerous virtual loudspeakers were set on the boundary to simulate a WFS system. Room impulse responses and head-related impulse responses were calculated by computer simulation. Then, binaural impulse responses were synthesized as combinations of RIRs and HRIRs. We picked up the boundary points so that upper-limit frequency without the spatial aliasing of BRIRs was systematically controlled. Listening test was conduct...