On Direct Aeroacoustics Calculations of the Vocal Tract
Voice production and the verbal expression through speech are crucial components of human communication. The human voice is not just conveying information directly through words, but also indirectly as paralinguistic information such as the speaker’s emotional state through tonality (Zhang, J Acoust Soc Am, 140(4):2614–2635, (2016), ). As such, voice is generated through a two-part process: First, a source signal is produced by the vocal folds that are pulsating the lung pressure and volumetric flow rate in a particular frequency through periodic opening and closing. Second, the vocal tract causes an attenuation or amplification of this source signal at certain frequencies depending on its specific shape. The voice generation process can therefore be described by a source-filter model with the vocal folds acting as the source and the vocal tract as an acoustic filter (Titze, Alipour, The myoelastic aerodynamic theory of phonation. National Center for Voice and Speech, (2006), ). Thus, we are able to produce different vowels and sounds as we manipulate the vocal tract during phonation.
This work is supported by the Swedish Research Council (Vetenskapsrådet) through the grant VR 621-2012-4256. The MRI scans and Helmholtz eigenfrequencies in Fig. 4 were obtained by the Speech Modelling Group from the Department of Mathematics and Systems Analysis at Aalto University, Finland (http://speech.math.aalto.fi). The Swedish National Infrastructure for Computing (SNIC) is acknowledged for the computational resources used for the simulations.