To examine the acoustical effects of complicated cross section shape and bent form of the nasal tract, sound propagation in the nasal tract is investigated. Finite Element Method Analysis (FEM) has been applied for the acoustic models of the nasal tract. The acoustic models are so constructed that each model has different degree of simplification of actual morphological measurements obtained by MRI (Magnetic Resonance Imaging Technology). Comparing the resulting acoustical characteristics of those models, it is found that how the maxillary sinuses and the right-left asymmetry affect the pole-zero configuration of sound spectra of nasal speech, and how the complicated cross section shape of nasal tract affects the sound flow in the tract.
Bibliographic reference. Suzuki, Hisayoshi / Nakai, Takayoshi / Sakakibara, Hiroshi (1995): "3-d fem analysis of sound propagation in the nasal tract", In EUROSPEECH-1995, 1301-1304.