Fig 1.
Experimental setup for measuring the vocal tract transfer function.
(A) The mouth of the vocal tract model is open and the pressure P1 is measured at the glottis. (B) The mouth of the model is closed and the pressure P3 is measured right in front of the closed mouth.
Fig 2.
Theoretical model of the measurement setup.
Equivalent acoustic circuits for the measurement situations in Fig 1A and 1B, respectively.
Fig 3.
Printed and finite element models.
(A) Different views of the 3D-printed model of /a/. (B), (C) and (D) Finite element models of /a/, /u/ and /i/. For each model, the surface was partitioned into three regions representing the glottis, the lip region and the vocal tract walls.
Fig 4.
Spectra of pressure signals measured at the glottis (P1), in front of the closed mouth (P3) and without the models (Pref) for the models /a/ (A), /u/ (B), /i/ (C) and /Ə/ (D).
Fig 5.
Experimentally determined pressure ratios at the lips.
Ratio of the pressure spectra measured in front of the closed mouth (P3) and without the models (Pref) for all four models.
Fig 6.
Transfer functions P1/P3, P1/Pref, and the simulated transfer functions HFEM for the models /a/ (A), /u/ (B), /i/ (C) and /Ə/ (D).
Table 1.
Formant frequencies in Hz of the simulated and measured transfer functions and their relative deviations in %.
Table 2.
Bandwidths in Hz of the simulated and measured transfer functions and their absolute deviations in Hz.
Table 3.
Amplitudes in dB of the simulated and measured transfer functions and their absolute deviations in dB.