Research on Perception Sensitivity of Elevation Angle in 3D Sound Field

The development of virtual reality and three-dimensional (3D) video inspired the concern about 3D audio, 3D audio aims at reconstructing the spatial information of original signals, the spatial perception sensitivity and minimum audible angle (MAA) would help to improve the accuracy of reconstructing signals. The measurements and analysis of MAA thresholds are limited to the azimuth angle at present, lacking of elevation angles quantitative analyzing, it is unable to build the complete spatial perception model of 3D sound field, which could be used in accurate 3D sound field reconstruction. In order to study the perception sensitivity of elevation angle at different locations in 3D sound field, subjective listening tests were conducted, elevation minimum audible angle (EMAA) thresholds at 144 different locations in 3D sound field were tested. The tests were referred to the quantitative analysis of azimuth minimum audible angle (AMAA) thresholds of human ear, based on psychoacoustic model and manikin. The results show that the EMAA thresholds have obvious dependence on elevation angle, thresholds vary between 3\(^{\circ }\) and 30\(^{\circ }\), reach the minimum value at the ear plane (elevation angle: 0\(^{\circ }\)), increase proportional linearly as the elevation angle departs from the ear plane and reach a relative maximum value on both sides (elevation angle: \(-30^{\circ }\) and 90\(^{\circ }\)). Besides, the EMAA thresholds are dependent upon azimuth angle too, thresholds reach the minimum value around median plane (azimuth angle: 0\(^{\circ }\)).