Effect of the losses in the vocal tract

The cross-sectional areas of the vocal tract are determined for the lossy and lossless cases by using the pole-zero models obtained from the electrical equivalent circuit of the vocal tract and the system identification method. The cross-sectional areas are used to compare the lossy and lossless cases. In the lossy case, the internal losses due to wall vibration, heat conduction, air friction and viscosity are considered. That is, the complex poles and zeros obtained from the models are used without eliminating their real parts. But, in the lossless case, only the imaginary parts of complex poles and zeros are used. When the cross-sectional areas obtained for two cases are investigated, the constriction point of the tongue becomes more obvious in the lossy case compared with the lossless case and the vocal tract shapes are similar to those of the Ishizaka-Flanagan model.