A model to represent propagation and radiation of higher-order modes for 3-d vocal-tract configuration

For the representation of acoustic characteristics of threedimensional vocal-tract shapes, it is necessary to consider the e ects of higher-order modes. This paper proposes an acoustic model of the vocal-tract which incorporates the coupling of the higher-order modes, including both propagative and evanescent modes. A cascaded structure of acoustic tubes connected asymmetrically is introduced as a physical approximation of the vocal-tract. The acoustic characteristics, which are dependent not only on the vocal-tract area function but also on the vocal-tract con guration, can be investigated by the proposed model. Preliminary results of numerical computations for relatively simple con gurations suggest that additional resonances at frequencies above 4.3kHz are formed by the propagative higher-order modes, while those at frequencies below 3 kHz are in uenced by the evanescent higher-order modes. These results are also con rmed by the FEM simulations.