scholarly journals Aeroacoustic Sound Source Characterization of the Human Voice Production-Perturbed Convective Wave Equation

2021 ◽  
Vol 11 (6) ◽  
pp. 2614
Author(s):  
Stefan Schoder ◽  
Paul Maurerlehner ◽  
Andreas Wurzinger ◽  
Alexander Hauser ◽  
Sebastian Falk ◽  
...  
Keyword(s):  
Wave Equation ◽  
Time Derivative ◽  
Maximum Amplitude ◽  
Vocal Folds ◽  
Far Field ◽  
Source Characterization ◽  
Turbulent Structures ◽  
Sound Sources ◽  
Voice Production ◽  
Human Voice

The flow-induced sound sources of human voice production are investigated based on a validated voice model. This analysis is performed using a hybrid aeroacoustic workflow based on the perturbed convective wave equation. In the first step, the validated 3D incompressible turbulent flow simulation is computed by the finite volume method using STARCCM+. In a second step, the aeroacoustic sources are evaluated and studied in detail. The formulation of the sound sources is compared to the simplification (neglecting the convective sources) systematically using time-domain and Fourier-space analysis. Additionally, the wave equation is solved with the finite element solver openCFS to obtain the 3D sound field in the acoustic far-field. During the detailed effect analysis, the far-field sound spectra are compared quantitatively, and the flow-induced sound sources are visualized within the larynx. In this contribution, it is shown that the convective part of the sources dominates locally near the vocal folds (VFs) while the local time derivative of the incompressible pressure is distributed in the whole supra-glottal area. Although the maximum amplitude of the time derivative is lower, the integral contribution dominates the sound spectrum. As a by-product of the detailed perturbed convective wave equation source study, we show that the convective source term can be neglected since it only reduces the validation error by 0.6%. Neglecting the convective part reduces the algorithmic complexity of the aeroacoustic source computation of the perturbed convective wave equation and the stored flow data. From the source visualization, we learned how the VF motion transforms into specific characteristics of the aeroacoustic sources. We found that if the VFs are fully closing, the aeroacoustic source terms yield the highest dynamical range. If the VFs are not fully closing, VFs motion does not provide as much source energy to the flow-induced sound sources as in the case of a healthy voice. As a consequence of not fully closing VFs, the cyclic pulsating velocity jet is not cut off entirely and therefore turbulent structures are permanently present inside the supraglottal region. These turbulent structures increase the broadband component of the voice signal, which supports research results of previous studies regarding glottis closure and insufficient voice production.

scholarly journals Impact of the Sub-Grid Scale Turbulence Model in Aeroacoustic Simulation of Human Voice

2021 ◽  
Vol 11 (4) ◽  
pp. 1970
Author(s):  
Martin Lasota ◽  
Petr Šidlof ◽  
Manfred Kaltenbacher ◽  
Stefan Schoder
Keyword(s):  
Sound Propagation ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Equation Model ◽  
Voice Production ◽  
Human Voice ◽  
Large Eddy ◽  
Aeroacoustic Simulation ◽  
Scale Turbulence ◽  
The One

In an aeroacoustic simulation of human voice production, the effect of the sub-grid scale (SGS) model on the acoustic spectrum was investigated. In the first step, incompressible airflow in a 3D model of larynx with vocal folds undergoing prescribed two-degree-of-freedom oscillation was simulated by laminar and Large-Eddy Simulations (LES), using the One-Equation and Wall-Adaptive Local-Eddy (WALE) SGS models. Second, the aeroacoustic sources and the sound propagation in a domain composed of the larynx and vocal tract were computed by the Perturbed Convective Wave Equation (PCWE) for vowels [u:] and [i:]. The results show that the SGS model has a significant impact not only on the flow field, but also on the spectrum of the sound sampled 1 cm downstream of the lips. With the WALE model, which is known to handle the near-wall and high-shear regions more precisely, the simulations predict significantly higher peak volumetric flow rates of air than those of the One-Equation model, only slightly lower than the laminar simulation. The usage of the WALE SGS model also results in higher sound pressure levels of the higher harmonic frequencies.

NUMERICAL SOLUTION OF THE ACOUSTIC WAVE EQUATION AT THE LIMIT BETWEEN NEAR AND FAR FIELD PROPAGATION

2001 ◽  
Vol 12 (10) ◽  
pp. 1497-1507 ◽  
Author(s):  
ERICH STOLL ◽  
STEFAN DANGEL
Keyword(s):  
Wave Equation ◽  
Acoustic Wave ◽  
Seismic Waves ◽  
Near Field ◽  
Three Dimensional ◽  
Low Frequency ◽  
Far Field ◽  
Acoustic Wave Equation ◽  
Sound Sources ◽  
Continuous Waves

The acoustic wave equation is solved numerically for two and three-dimensional systems at the limit between near and far field propagation. Our results show that for large sound velocities, corresponding to wavelengths larger than the system, near field properties are dominant. When the near field conditions are no longer satisfied, standing waves close to the sound emitters and interference patterns between the near field and far field solutions appear. Our procedure is applied to sound sources, which broadcast coherent and continuous waves as well as to sources emitting bursts of incoherent and uncorrelated waves. Both cases can be used to simulate the spreading of low frequency seismic waves observed close to volcanoes and hydrocarbon reservoirs.

SIMULATIONS OF VOCAL FOLDS WITH AN ANALOG CIRCUIT

1999 ◽  
Vol 09 (06) ◽  
pp. 1075-1088 ◽  
Author(s):  
ROBERT REUTER ◽  
REINHOLD ORGLMEISTER ◽  
HANSPETER HERZEL
Keyword(s):  
Analog Circuit ◽  
Narrow Band ◽  
Phase Locking ◽  
Vocal Folds ◽  
Complex Signals ◽  
Voice Production ◽  
Voice Source ◽  
Human Voice ◽  
Return Maps ◽  
Left Right Asymmetry

The human voice source generates complex signals including subharmonics and toroidal oscillations. Essential features of voice production are covered by two-mass models where each vocal fold is represented by two oscillators. We present a related analog circuit which allows online analysis of the generated complex signals. Using narrow-band spectrograms various bifurcations due to left–right asymmetry are monitored. Time series, spectra, return maps, and response measurements provide further detailed information about phase-locking and toroidal oscillations. Finally, possible clinical applications are discussed.

High-Speed Imaging to Study an Auto-Oscillating Vocal Fold Replica for Different Initial Conditions

2017 ◽  
Vol 09 (05) ◽  
pp. 1750064 ◽  
Author(s):  
A. Van Hirtum ◽  
X. Pelorson
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Initial Conditions ◽  
Vocal Folds ◽  
High Speed Imaging ◽  
Human Voice ◽  
Manual Intervention ◽  
Geometrical Features ◽  
Upstream Pressure

Experiments on mechanical deformable vocal folds replicas are important in physical studies of human voice production to understand the underlying fluid–structure interaction. At current date, most experiments are performed for constant initial conditions with respect to structural as well as geometrical features. Varying those conditions requires manual intervention, which might affect reproducibility and hence the quality of experimental results. In this work, a setup is described which allows setting elastic and geometrical initial conditions in an automated way for a deformable vocal fold replica. High-speed imaging is integrated in the setup in order to decorrelate elastic and geometrical features. This way, reproducible, accurate and systematic measurements can be performed for prescribed initial conditions of glottal area, mean upstream pressure and vocal fold elasticity. Moreover, quantification of geometrical features during auto-oscillation is shown to contribute to the experimental characterization and understanding.

Monitoring Vocal Fold Abduction through Vocal Fold Contact Area

1988 ◽  
Vol 31 (3) ◽  
pp. 338-351 ◽  
Author(s):  
Martin Rothenberg ◽  
James J. Mahshie
Keyword(s):  
Contact Area ◽  
Time Variation ◽  
Vocal Fold ◽  
Thyroid Cartilage ◽  
Electrical Conductance ◽  
Vocal Folds ◽  
Linear Phase ◽  
Voice Production ◽  
Voiced Speech ◽  
High Pass

A number of commercial devices for measuring the transverse electrical conductance of the thyroid cartilage produce waveforms that can be useful for monitoring movements within the larynx during voice production, especially movements that are closely related to the time-variation of the contact between the vocal folds as they vibrate. This paper compares the various approaches that can be used to apply such a device, usually referred to as an electroglottograph, to the problem of monitoring the time-variation of vocal fold abduction and adduction during voiced speech. One method, in which a measure of relative vocal fold abduction is derived from the duty cycle of the linear-phase high pass filtered electroglottograph waveform, is developed in detail.

scholarly journals Common Terminology and Acoustic Measures for Human Voice and Birdsong

2019 ◽  
Vol 62 (1) ◽  
pp. 60-69
Author(s):  
Areen Badwal ◽  
JoHanna Poertner ◽  
Robin A. Samlan ◽  
Julie E. Miller
Keyword(s):  
Acoustic Analysis ◽  
Voice Production ◽  
Acoustic Measures ◽  
Human Voice ◽  
Song Analysis ◽  
Core Set ◽  
Standard Terminology ◽  
Cepstral Peak Prominence ◽  
Two Measures ◽  
Similarities And Differences

Purpose The zebra finch is used as a model to study the neural circuitry of auditory-guided human vocal production. The terminology of birdsong production and acoustic analysis, however, differs from human voice production, making it difficult for voice researchers of either species to navigate the literature from the other. The purpose of this research note is to identify common terminology and measures to better compare information across species. Method Terminology used in the birdsong literature will be mapped onto terminology used in the human voice production literature. Measures typically used to quantify the percepts of pitch, loudness, and quality will be described. Measures common to the literature in both species will be made from the songs of 3 middle-age birds using Praat and Song Analysis Pro. Two measures, cepstral peak prominence (CPP) and Wiener entropy (WE), will be compared to determine if they provide similar information. Results Similarities and differences in terminology and acoustic analyses are presented. A core set of measures including frequency, frequency variability within a syllable, intensity, CPP, and WE are proposed for future studies. CPP and WE are related yet provide unique information about the syllable structure. Conclusions Using a core set of measures familiar to both human voice and birdsong researchers, along with both CPP and WE, will allow characterization of similarities and differences among birds. Standard terminology and measures will improve accessibility of the birdsong literature to human voice researchers and vice versa. Supplemental Material https://doi.org/10.23641/asha.7438964

On the hydrodynamic and acoustic nature of pressure proper orthogonal decomposition modes in the near field of a compressible jet

2017 ◽  
Vol 836 ◽  
pp. 998-1008 ◽  
Author(s):  
Matteo Mancinelli ◽  
Tiziano Pagliaroli ◽  
Roberto Camussi ◽  
Thomas Castelain
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Time Pressure ◽  
Near Field ◽  
Pressure Fluctuations ◽  
Orthogonal Decomposition ◽  
Spectral Energy ◽  
Far Field ◽  
Turbulent Structures ◽  
Proper Orthogonal ◽  
Compressible Jet

In this work an experimental investigation of the near-field pressure of a compressible jet is presented. The proper orthogonal decomposition (POD) of the pressure fluctuations measured by a linear array of microphones is performed in order to provide the streamwise evolution of the jet structure. The wavenumber–frequency spectrum of the space–time pressure fields re-constructed using each POD mode is computed in order to provide the physical interpretation of the mode in terms of hydrodynamic/acoustic nature. Specifically, non-radiating hydrodynamic, radiating acoustic and ‘hybrid’ hydro-acoustic modes are found based on the phase velocity associated with the spectral energy bumps in the wavenumber–frequency domain. Furthermore, the propagation direction in the far field of the radiating POD modes is detected through the cross-correlation with the measured far-field noise. Modes associated with noise emissions from large/fine scale turbulent structures radiating in the downstream/sideline direction in the far field are thus identified.

The Extra-normal Voice

2014 ◽  
pp. 728-750
Author(s):  
Michael Edward Edgerton
Keyword(s):  
Complex Networks ◽  
Crucial Role ◽  
Sound Production ◽  
Power Source ◽  
Sound Sources ◽  
New Developments ◽  
Voice Production ◽  
Multiple Parameters ◽  
Normal Voice ◽  
Production Apparatus

This chapter presents an overview of new developments in vocal exploration. Beginning with a discussion of multiple parameters involved in voice production, this chapter identifies the crucial role that non-linear phenomena has in the performance of the extra-normal voice. In this article, two related taxonomies are presented (source production related to degree of voicing; emphases within the acoustic framework of power, source, resonance, and articulation) that may be used as powerful generative tools for the production of multiple sound sources, filtering processes, and aerodynamic effects, etc. The paper then posits how scaled, multidimensional networks may be used to intelligently explore all elements of the acoustic sound production apparatus and not solely articulation, as is seen with some proponents of complex networks. In this discussion, it will be presented how fully scaling each parameter space will encompass far reaching benefits by engaging with little traversed regions of the total vocal topography.

scholarly journals Decay of solutions of the wave equation in expanding cosmological spacetimes

2019 ◽  
Vol 16 (01) ◽  
pp. 35-58
Author(s):  
João L. Costa ◽  
José Natário ◽  
Pedro F. C. Oliveira
Keyword(s):  
Wave Equation ◽  
Initial Data ◽  
Decay Rate ◽  
Time Derivative ◽  
Iteration Scheme ◽  
Higher Order ◽  
Accelerated Expansion ◽  
De Sitter ◽  
Decay Of Solutions ◽  
Partial Energy

We study the decay of solutions of the wave equation in some expanding cosmological spacetimes, namely flat Friedmann–Lemaître–Robertson–Walker (FLRW) models and the cosmological region of the Reissner–Nordström–de Sitter (RNdS) solution. By introducing a partial energy and using an iteration scheme, we find that, for initial data with finite higher order energies, the decay rate of the time derivative is faster than previously existing estimates. For models undergoing accelerated expansion, our decay rate appears to be (almost) sharp.

Design of Apparatus for Studying Aerodynamics of Voice Production

2004 ◽  
Author(s):  
Michael Barry
Keyword(s):  
Flow Visualization ◽  
Vocal Fold ◽  
Sound Production ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Flow Speed ◽  
Working Fluid ◽  
Voice Production ◽  
Experimental Apparatus ◽  
Glottal Flow

The design and testing of an experimental apparatus for in vitro study of phonatory aerodynamics (voice production) in humans is presented. The presentation includes not only the details of apparatus design, but flow visualization and Digital Particle Image Velocimetry (DPIV) measurements of the developing flow that occurs during the opening of the constriction from complete closure. The main features of the phonation process have long been understood. A proper combination of air flow from the lungs and of vocal fold tension initiates a vibration of the vocal folds, which in turn valves the airflow. The resulting periodic acceleration of the airstream through the glottis excites the acoustic modes of the vocal tract. It is further understood that the pressure gradient driving glottal flow is related to flow separation on the downstream side of the vocal folds. However, the details of this process and how it may contribute to effects such as aperiodicity of the voice and energy losses in voiced sound production are still not fully grasped. The experimental apparatus described in this paper is designed to address these issues. The apparatus itself consists of a scaled-up duct in which water flows through a constriction whose width is modulated by motion of the duct wall in a manner mimicking vocal fold vibration. Scaling the duct up 10 times and using water as the working fluid allows temporally and spatially resolved measurements of the dynamically similar flow velocity field using DPIV at video standard framing rates (15Hz). Dynamic similarity is ensured by matching the Reynolds number (based on glottal flow speed and glottis width) of 8000, and by varying the Strouhal number (based on vocal fold length, glottal flow speed, and a time scale characterizing the motion of the vocal folds) ranging from 0.01 to 0.1. The walls of the 28 cm × 28 cm test section and the vocal fold pieces are made of clear cast acrylic to allow optical access. The vocal fold pieces are 12.7 cm × 14 cm × 28 cm and are rectangular in shape, except for the surfaces which form the glottis, which are 6.35 cm radius half-circles. Dye injection slots are placed on the upstream side of both vocal field pieces to allow flow visualization. Prescribed motion of the vocal folds is provided by two linear stages. Linear bearings ensure smooth execution of the motion prescribed using a computer interface. Measurements described here use the Laser-Induced Fluorescence (LIF) flow visualization and DPIV techniques and are performed for two Strouhal numbers to assess the effect of opening time on the development of the glottal jet. These measurements are conducted on a plane oriented perpendicular to the glottis, at the duct midplane. LIF measurements use a 5W Argon ion laser to produce a light sheet, which illuminates the dye injected through a slot in each vocal fold piece. Two dye colors are used, one for each side. Quantitative information about the velocity and vorticity fields are obtained through DPIV measurements at the same location as the LIF measurements.

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