Directivity of Spherical Polyhedron Sound Source Used in Near-Field HRTF Measurements

The omnidirectional character is one of important requirements for the sound source used in near-field head-related transfer function (HRTF) measurements. Based on the analysis on the radiation sound pressure and directivity character of various spherical polyhedron sound sources, a spherical dodecahedral sound source with radius of 0.035 m is proposed and manufactured. Theoretical and measured results indicate that the sound source is approximately omnidirectional below the frequency of 8 kHz. In addition, the sound source has reasonable magnitude response from 350 Hz to 20 kHz and linear phase characteristics. Therefore, it is suitable for the near-field HRTF measurements.