Characteristics of two-dimensional finite difference techniques for vocal tract analysis and voice synthesis

Both digital waveguide and finite difference techniques are numerical methods that have been demonstrated as appropriate for acoustic modelling applications. Whilst the application of the digital waveguide mesh to vocal tract modelling has been the subject of previous work, the application of comparable finite difference techniques is as yet untested. This study explores the characteristics of such a finite-difference approach to two-dimensional vocal tract modelling. Initial results suggest that finite difference techniques alone are not ideal, due to the limitation of non-dynamic behaviour and poor representation of admittance discontinuities in the approximation of threedimensional geometries. They do however introduce robust boundary formulations, and have a valid and useful application in modelling non-vital static volumes, particularly the nasal tract.