Angular resolution of radiation characteristics required to reproduce uttered speech in all three-dimensional directions

Abstract

For applications in six-degrees-of-freedom (6DoF) content reproduction, this study investigates the angular resolution of radiation characteristics required to reproduce uttered speech in all three-dimensional (3D) directions as an angle at which humans are unable to perceive a difference in the comprehensive audio quality change between adjacent radiation directions. The radiation characteristics of uttered Japanese speech for female and male speakers are measured in three cross-sections, namely the horizontal, median, and frontal planes. The measurements are obtained using a spherical jig for 3D microphone arrangement. A subjective evaluation is conducted to clarify the impact of the difference in the radiation directions on the audio quality of uttered speech in each cross-section. Finally, a statistical analysis of the experimental results shows that the required angular resolutions are 30° relative to the horizontal plane, 30° relative to the median plane, and 60° relative to the frontal plane. Therefore, it is concluded that an angular resolution of at least 30° is required to reproduce uttered speech in all 3D directions.