This paper details software under development that uses the digital waveguide physical model to represent the sound creation mechanism and environment associated with the production of speech, specifically the human vocal tract. Focus is directed towards a comparison between the existing 1D waveguide method, on which several studies have already been conducted, and the developing 2D waveguide mesh method. The construction of the two models and the application of the tract geometry is examined, in addition, the inclusion of dynamic articulatory variations to increase the ability of such systems to create natural sounding speech is discussed. Results obtained from each suggest that the 2D model is capable of producing similarly accurate vowel spectra to that already accomplished with the 1D version, although speech-like sounds created with the 2D mesh appear to exhibit greater realism.

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This paper presents a study of an articulatory-based speech synthesis based on a 2D-Digital Waveguide Mesh (2D-DWM) to model acoustic wave propagation in the oral tract. It is employed to study the effects of changing oral tract area, and in particular, of moving the articulators during the production of diphthongs. The operation of the synthesizer including details of how diphthongs are produced are discussed. The results support earlier findings that the wall reflection coefficient is inversely proportional to the formant bandwidth.

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