To stabilize a location of a
sound image.SOLUTION: In a side of quadrangle on a spherical surface in which four speakers surrounding a target
sound image position are set as a peak, it is assumed that the virtual speaker is positioned onto the side positioned at a lower side. By performing a three-dimension VBAP from the virtual speaker and the two speakers on an upper right and an upper left, each
gain of the two speaker on the upper right and the upper left for positioning a
sound image to the target sound image position and the virtual speaker is calculated. Further, by performing a secondary VBAP of the speakers in a lower right and a lower left, each
gain of the speakers on the lower right and the lower left for positioning the sound image to the virtual speaker is calculated. The
gain obtained by multiplying the gain of the virtual speaker to the gain is a gain of the speaker in the lower right and the lower left for positioning the sound image to the target sound image position. The present technique is adapted to the voice
processing device.SELECTED DRAWING: Figure 7