Pilot study on the influence of spatial resolution of human voice directivity on speech perception

A perceptual threshold related to spatial resolution of the human voice directivity was determined through a listening test of similarity (MUSHRA). Directivity data of an artificial talking head measured at high spatial resolution (spherical harmonics order 35) was the input of a room acoustics simulation software (RAVEN) to build sound stimuli in various room acoustic conditions and source-receiver arrangements, with different voices. Results showed that, at spherical harmonics order 8 and above, the voice signal was not anymore perceived as significantly different from the greatest resolution. An analytical model was proposed and showed good agreement with the listening test results.