Acoustic length correction of duct extension into a cylindrical chamber

Kang, Zhongxu; Ji, Zhenlin

doi:10.1016/j.jsv.2007.11.005

Cited by 35 publications

(14 citation statements)

References 13 publications

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“…5). This can be understood as an artificial lengthening of the differential duct where the discontinuity takes place (see, e.g., Kang and Ji, 2008), inducing the shift to the left of the 2D and 3D formants; a phenomenon that obviously cannot naturally occur in the 1D case. Note that the initial condition in Eq.…”

Section: Resultsmentioning

confidence: 99%

Two-dimensional vocal tracts with three-dimensional behavior in the numerical generation of vowels

Arnela

Guasch

2014

The Journal of the Acoustical Society of America

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Two-dimensional (2D) numerical simulations of vocal tract acoustics may provide a good balance between the high quality of three-dimensional (3D) finite element approaches and the low computational cost of one-dimensional (1D) techniques. However, 2D models are usually generated by considering the 2D vocal tract as a midsagittal cut of a 3D version, i.e., using the same radius function, wall impedance, glottal flow, and radiation losses as in 3D, which leads to strong discrepancies in the resulting vocal tract transfer functions. In this work, a four step methodology is proposed to match the behavior of 2D simulations with that of 3D vocal tracts with circular cross-sections. First, the 2D vocal tract profile becomes modified to tune the formant locations. Second, the 2D wall impedance is adjusted to fit the formant bandwidths. Third, the 2D glottal flow gets scaled to recover 3D pressure levels. Fourth and last, the 2D radiation model is tuned to match the 3D model following an optimization process. The procedure is tested for vowels /a/, /i/, and /u/ and the obtained results are compared with those of a full 3D simulation, a conventional 2D approach, and a 1D chain matrix model.

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Section: Resultsmentioning

confidence: 99%

Two-dimensional vocal tracts with three-dimensional behavior in the numerical generation of vowels

Arnela

Guasch

2014

The Journal of the Acoustical Society of America

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“…Only some small formant deviations (see also Table I) are produced for vowel [A] (e.g., the formants F4, F5, and F6) and for vowel [u] (e.g., the formant F6). These differences can be attributed to the bending phenomena of the propagating front waves produced at large area discontinuities (see, e.g., Kang and Ji, 2008), which should be different depending on the cross-sectional shape. These phenomena are typically considered in 1D approaches by introducing inner-length corrections at the sudden expansions/ constrictions of the vocal tract in order to correct the formant location (see, e.g., Sondhi, 1983, where this effect is approximated with expressions that consider circular cross-sections).…”

Section: B Effects Of the Number Of Cross-sectionsmentioning

confidence: 99%

Influence of vocal tract geometry simplifications on the numerical simulation of vowel sounds

Arnela

Dabbaghchian

Blandin

et al. 2016

The Journal of the Acoustical Society of America

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For many years, the vocal tract shape has been approximated by one-dimensional (1D) area functions to study the production of voice. More recently, 3D approaches allow one to deal with the complex 3D vocal tract, although area-based 3D geometries of circular cross-section are still in use. However, little is known about the influence of performing such a simplification, and some alternatives may exist between these two extreme options. To this aim, several vocal tract geometry simplifications for vowels [A], [i], and [u] are investigated in this work. Six cases are considered, consisting of realistic, elliptical, and circular cross-sections interpolated through a bent or straight midline. For frequencies below 4-5 kHz, the influence of bending and cross-sectional shape has been found weak, while above these values simplified bent vocal tracts with realistic cross-sections are necessary to correctly emulate higher-order mode propagation. To perform this study, the finite element method (FEM) has been used. FEM results have also been compared to a 3D multimodal method and to a classical 1D frequency domain model.

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“…Despite extensive historical and ongoing investigations into the physics and understanding of Helmholtz resonators by experimental and theoretical [ 5 – 7 , 2 ] and numerical approaches [ 7 , 8 ], little has been published on attempts to use a Helmholtz resonator as a measurement device. A preliminary investigation by Nishizu et al [ 9 ] indicated successful volume measurements on solids were possible using a Helmholtz resonator in which part of the chamber volume was displaced by a sample volume to be measured; the use of a closed Helmholtz resonator for measuring the volume of a liquid in micro-gravity has been reported by Nakano et al [ 10 ].…”

Section: Introductionmentioning

confidence: 99%