High-Resolution Directivity Measurements of an Artificial Head and Mouth Shaped to Three Vowels

The directivity of the human voice has been studied since the early twentieth century using different measurement systems with progressively higher spatial resolution. Artificial heads and mouths have been used because of their ability to repeat a given sound production, hence allowing sequential measurements of directivity with a reduced number of microphones and still achieving high spatial resolution. Unlike most artificial heads, whose external geometry is abstracted, this study uses a custom 3D-printed head with detailed geometry and three different mouth openings, all based on 3D scans from magnetic resonance imaging data. The impulse response measurements were performed using a 3D robotic arm, resulting in directivity data with 5° resolution in both azimuth and elevation. The measured directivity patterns are consistent with previous research on energy distribution in space over angles (azimuth and elevation) and frequency, with a higher spatial resolution and for different mouth shapes. The resulting data set is made available in several standardized file formats to facilitate accurate voice directivity simulations in virtual acoustic environments.