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Topic: Vocal tract


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In the News (Wed 25 Nov 09)

  
  Estimates of Pitch and Vocal Tract Length from Recorded Vocalizations of Purported Bigfoot
Assuming 5' 11" to be the height for an average man, 115 Hz pitch, and 17.8 cm his average tract length, the creature or creatures on the recording, using all data shown, may be estimated to have a proportional height of 7' 3" by pitch or 6' 4" by tract length.
It is the opinion of the authors that the vocalizations on the tape were recorded at the speed they appear to be because the articulation rate and the range of vocal tract lengths are quite broad at constant pitch during the growl or "grr" sounds.
The formants and corresponding short vocal tract lengths found indicate the likelihood that the creatures could be able to whistle utilizing only a part of their vocal tract.
www.rfthomas.clara.net /papers/kirlin.html   (3150 words)

  
 Digital speech synthesizer having an analog delay line vocal tract - Patent 4264783
In this respect, the human vocal tract exhibits the acoustical characteristics of an acoustic tube whose cross-sectional dimensions are small relative to the wavelengths of the frequencies generated.
The vocal amplitude control signal (VA) is generated whenever a phoneme having a voiced component is present, and is utilized to control the intensity of the voiced excitation signal that is injected into the vocal tract.
The embodiment of the vocal tract 28 described herein is utilized in the present system because of the exceptional quality of speech produced thereby given the relative simplicity of the circuit and the minimum number of control signal parameters required.
www.freepatentsonline.com /4264783.html   (13922 words)

  
 Vocal Tract -- Recommendations and Resources   (Site not responding. Last check: 2007-10-17)
The vocal tract is that cavity in animals and humans, where sound that is produced at the sound source (larynx in mammals; syrinx in birds) is filtered.
These tracts were in fact lengthy theological discourses that sought to establish the continuity between the Church of England and the patristic period of church history.
The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and expels the remaining waste.
www.becomingapediatrician.com /health/162/vocal-tract.html   (964 words)

  
 Voice Resonances
Sundberg models the vocal tract as a closed tube resonator, suggesting that the three prominent formants seen in vowel sounds correspond to the harmonics 1,3,5.
If the vocal tract is considered to be a cavity resonator, then it can be seen that the position of the tongue, the area of opening of the mouth, and any changes which affect the volume of the cavity will retune the resonance.
The vocal tract acts as a resonator with frequencies which can be modulated by the articulators, forming the vocal formants which make vowel sounds recognizable.
hyperphysics.phy-astr.gsu.edu /hbase/music/vocres.html   (375 words)

  
 A Model of the Human Vocal Tract
Movement of the velum has two effects: it alters the shape of the oral branch of the vocal tract and, in addition, it changes the size of the coupling port to the fixed nasal tract.
For example, acoustic excitation of the vocal tract transfer function is most commonly specified as an acoustic waveform, rather than provided by simulating the physiological and aerodynamic factors of phonation.
Figure 9 shows, at the top, midsagittal vocal tract outlines for the major transition points (key frames) in the simulation of the articulations of four utterances: /banana/, /bandana/, /badnana/, /baddata/.
www.haskins.yale.edu /featured/heads/MMSP/tract.html   (1685 words)

  
 Vocal Tract Imaging   (Site not responding. Last check: 2007-10-17)
Their primary interest was in correlating the vocal tract length measured for an /e/ vowel to resonance frequencies (formants) predicted by theory.
Imaging the vocal tract with MRI is a trade-off of image quality and accuracy for safety of the subject.
The particular vocal tract shape is that of the vowel /a/ (as in "hot").
web1.dcpa.org /brad_html/imaging.html   (1152 words)

  
 Medicine In The Vocal Arts   (Site not responding. Last check: 2007-10-17)
The severity of laryngeal inflammation, the degree of vocal impairment, and the short-term "performance" schedule of the vocalist are all important factors in the decision-making process and the approach to treatment.
Vocal nodules, small discrete swellings at the junction of the anterior and middle thirds of the vocal folds, are common in vocalists, and are always the result of vocal trauma.
Vocal abuse in a vocal professional is tantamount to a musician's leaving his or her instrument out in the rain: it is inappropriate and neglectful.
www1.wfubmc.edu /voice/singers/vocal_arts.htm   (4730 words)

  
 Vocal Sound Production
Positioned at the base of the larynx in the vocal tract, these twin infoldings of mucous membrane act as the vibrator or "reed" during phonation.
While "vocal folds" is more descriptive than "vocal cords", there is some similarity to a vibrating string in that the pitch produced depends upon the length, mass and tension of the vocal folds.
The excitation of the vocal folds is however very different from the excitation of a string in that is is caused by the passage of air through the opening between the folds.
hyperphysics.phy-astr.gsu.edu /hbase/music/voice.html   (546 words)

  
 Vocal tract modelling   (Site not responding. Last check: 2007-10-17)
In the first attempts the vocal tract was modelled in the form of a chain of homogeneous tubes.
The vocal tract is made up of three cavities: the pharyngeal, oral and nasal cavities and their contribution to the acoustic properties of the vocal tract depend on their configuration and connection to the whole articulatory system.
Thus, the geometrical configuration of the vocal tract is subject to substantial variations during the articulation process.
www.ims.uni-stuttgart.de /phonetik/EGG/pagem5.htm   (728 words)

  
 Vocal Tract Development Laboratory
While acoustic theory indicates that vocal geometry is predictive of the spectrum shape of speech sounds, the relation between developmental changes in the vocal tract to changes in speech acoustics has not been adequately investigated.
This is due to the scarcity of quantitative information on the anatomic remodeling of the vocal tract during development.
The goal of this project is to gain a detailed understanding of the postnatal macroanatomic three dimensional (3D) development of the vocal tract structures in typically developing individuals and in individuals with atypical speech development due to chromosomal aberrations, such as Trisomy 21.
www.waisman.wisc.edu /vocal/index.htmlx   (286 words)

  
 Acoustics of the Voice   (Site not responding. Last check: 2007-10-17)
We have developed a device for measuring some important acoustic properties of the vocal tract non-invasively, in real-time, while the owner of the vocal tract is speaking or singing.
We then measure the impedance of the vocal tract in parallel with the external field using the response to this excitation signal.
One of the effects of a this shape in a brass instrument is to raise the frequencies of the resonances, especially those of the lower resonances.
www.phys.unsw.edu.au /speech   (1360 words)

  
 Vocal Vowels: Exploratorium Exhibit. Hollow plastic models of the human vocal tract turn the squawk of a duck call into ...
Note that while the plastic models are straight, the vocal tract is bent almost 90 degrees in the middle.
The chamber of each plastic model is shaped like your vocal tract - the cavity formed by your mouth and throat when you speak.
The plastic chambers pictures are aligned similar to your vocal tract with the vocal chords (duck call) at the bottom and the lips at the top.
www.exploratorium.edu /exhibits/vocal_vowels/vocal_vowels.html   (330 words)

  
 Source-Tract Acoustic Interaction and Voice Quality
Both he and Sundberg (1974) discuss the possible features of the vocal tract configuration that could cause two resonances to appear in a frequency range in which only one (the third vocal tract formant) is to be found during normal speech, and we shall not go into this topic further here.
As the vocal folds oscillate during voicing in the modal or chest register, the area of the glottis varies in a rather symmetrical, triangular-shaped pattern, as shown in the center of Figure 2.
However, as shown in the figure, the buildup in air flow as the vocal folds separate is delayed, primarily by the inertia of the vocal tract air below and above the glottis.
www.rothenberg.org /Sourcetractvq/Sourcetractvq.htm   (2948 words)

  
 the 3D Vocal Tract Project
The model, described in Engwall (1999a), consists of vocal and nasal tract walls, lips, teeth and tongue, represented as visually distinct articulators by different colours resembling the ones in a natural human vocal tract.
MR images were taken of the midsagittal plane and in full 3D for one speaker of Swedish, as exemplified by the MR image gallery and the animated gifs of a large part of the midsagittal corpus and an examples of the full 3D collection ('sj' of 'sjutton').
The MRI database was used to reconstruct the vocal tract shapes of Swedish phonemes in 3D.
www.speech.kth.se /multimodal/vocaltract.html   (600 words)

  
 Jaleel: Measuring the vocal tract using MRI
From an engineering point of view, we can think of the vocal tract as a resonator that filters the sounds produced by different sources: the periodic sounds produced with the vocal folds, and noisy sounds produced at the teeth, lips or elsewhere.
The shape of the vocal tract and thus the characteristics of the acoustic filter are determined by the articulators, which consist of the lips, tongue, velum, larynx and jaw.
Static measurements of the vocal tract might be imperfect because the shape of the vocal tract while the subject is sustaining a vowel could be different than if the a vowel was in a context.
www.ee.surrey.ac.uk /Personal/P.Jackson/Nephthys/jaleel.html   (1160 words)

  
 Air and Phonation
Let's not forget the lungs, which are in the chest, and are connected to the tube which goes up to the vocal cords (the trachea or windpipe).
If the vocal cords are held apart, air can flow between them without being obstructed, so that no noise is produced by the larynx.
This phonation is a combination of breath and voice, which occurs if the vocal cords do not close completely along their entire length while they are vibrating, the air which flows through the remaining aperture adds whisper to the vocal cord vibrations.
www.phon.ox.ac.uk /~jcoleman/phonation.htm   (762 words)

  
 Vocal Tract Response Characteristics   (Site not responding. Last check: 2007-10-17)
The exact resonance characteristics of the vocal tract are a function of many factors, but the two factors of primary importance are the length of the vocal tract and its shape, that is, the cross sectional area profile from glottis to lips.
Resonances in the vocal tract reinforce the sound energy of the source function at particular frequencies.
This is a relatively smooth and continuous function of frequency with peaks at frequencies corresponding to the resonant frequencies of the vocal tract.
www.asel.udel.edu /speech/tutorials/production/filter.htm   (245 words)

  
 Model of the vocal apparatus
The vocal tract parameters are similar to those of the two-dimensional vocal tract model of Mermelstein (Mermelstein, 1973), but have been extended to take into account the three-dimensional geometry of our model.
Like the vocal tract, the left and right vocal folds are assumed to be symmetric with respect to the midsagittal plane.
The cross-sectional area of the former was made to vary depending of the position of the velum in the vocal tract model.
wwwicg.informatik.uni-rostock.de /~piet/tract_model.html   (1572 words)

  
 BBC NEWS | Science/Nature | Monkey vocal ability investigated
Non-human primates were thought to have vocal tracts resembling simple tubes incapable of sophisticated articulation.
The researchers claim it is the first time both acoustic and anatomical data have supported the presence of a non-uniform vocal tract in a non-human primate.
The team X-rayed the vocal tracts of three adult Diana monkeys (two male, one female) from Baltimore Zoo and dissected the carcass of another which had died at the zoo.
news.bbc.co.uk /go/click/rss/0.91/public/-/2/hi/science/nature/4110977.stm   (534 words)

  
 Resonance tuning and vowel changes by sopranos   (Site not responding. Last check: 2007-10-17)
One can keep the vocal tract constant and change the pitch (eg humming, vocalise or singing 'la la la la la'), or one can keep the pitch the same and vary the vocal tract, which is what the Daleks on Dr Who do ('Ex-ter-min-ate').
Some time ago, the Swedish acoustician Johan Sundberg suggested that sopranos actually tune the resonance of their vocal tract to the note that they are singing: the original evidence for this was that they tend to open the mouth more as they sing successively higher notes.
Children have smaller heads and shorter vocal tracts, so one would expect that the resonances of their vocal tracts to occur at higher frequencies, so the overlap of pitch and resonance would occur at higher pitch.
www.phys.unsw.edu.au /~jw/soprane.html   (2242 words)

  
 Singers, Let's Prevent Vocal Problems!
Lawrence explains that water is extremely important in the normal functioning of the respiratory tract and of the vocal tract in particular.
Loeding advises vocal performers to avoid habits which dry out mucous membrane linings of the nose and throat, such as smoking and drinking alcoholic beverages, to drink eight to nine glasses of water a day, and to keep the air moist by using a vaporizer or turning on the hot shower.
As a depressant and muscle relaxant, alcohol may impair the control of the vocal folds and sensitivity of the throat, and the drying effect of alcohol can cause irritation in the tissues of the vocal tract eventually causing a raspy or hoarse voice.
www.voiceteacher.com /mathis.html   (3850 words)

  
 Modelling Biphonation - The Role of the Vocal Tract —
Instabilities of the human voice source appear in normal voices under certain conditions (newborn cries, vocal fry, creaky voice) and are symptomatic of voice pathologies.
Vocal instabilities are intimately related to bifurcations of the underlying nonlinear dynamical system.
We analyse in this paper bifurcations in 2-mass models of the vocal folds and study, in particular, how the incorporation of the vocal tract affects bifurcation diagrams.
itb.biologie.hu-berlin.de /Research/publications/mergell1997   (198 words)

  
 GnuSpeech Tube Resonance Model (TRM) vocal tract model for speech synthesis. Synthesizer App manual.
The first one is the mapping of the vocal cavities in terms of an area function describing the cross-sectional area perpendicular to the air stream from the glottis to the radiating surface at the lips.
The vocal tract was considered to comprise eight cylindrical regions corresponding to the regions distinguished by their effect on raising/lowering formant frequencies.
A tube model of the vocal tract emulates rather than simulates the resonant behaviour of the vocal tract because the tube behaviour maps directly onto the articulatory and acoustic characteristics of the real vocal tract, nasal passage and radiation impedance of nose and mouth, rather than simply imitating the resonance-mediated output.
pages.cpsc.ucalgary.ca /~hill/papers/synthesizer/body.html   (14728 words)

  
 Vocal Tract Visualization   (Site not responding. Last check: 2007-10-17)
The goal of vocal tract visualization is to allow us to view the vocal tract during unimpeded speech production.
Knowledge about the vocal tract is useful for clinical diagnosis of speech disorders, for providing more accurate data for acoustic modeling of speech production, and for studying the mechanics of vocal tract.
Ultrasound data collection is well suited to the vocal tract for several reasons.
www.cs.jhu.edu /~lundberg/vocal_tract_visualization/vtv.html   (399 words)

  
 Source-Tract Acoustic Interaction in Breathy Voice
The fact that not all of the vocal folds are in contact can be verified from the offset from zero area of the measured PGA waveform, or the offset from zero flow of the glottal air flow waveform.
Another effect to be expected during a voiced-unvoiced transition is a small decrease in the mice fundamental frequency (or increase in fundamental frequency during an unvoiced-voiced transition) as the phase shift at the fundamental frequency varies, since the frequency is the time derivative of the phase.
This is illustrated in Figure 37-5, in which the input to an analog model for the glottal source and vocal tract, using the "combined-source" case of Figure 37-3, was given the form and ac-to-dc ratio (relative offset from zero) of A
www.rothenberg.org /Sourcetractbv/Sourcetractbvprinterfriendly.htm   (5922 words)

  
 UCL Phonetics & Linguistics - Vocal Tract Demonstration
With VTDemo you can move the articulators in a 2D simulation of the vocal tract cavity and hear in real-time the consequences on the sound produced.
The VTCALCS program converts a set of seven vocal tract shape parameters into a vocal tract area function which is then used to filter a voicing signal from a modelled voice source.
Use the VT controls panel to manipulate the vocal tract shape.
www.phon.ucl.ac.uk /resource/vtdemo   (589 words)

  
 Singing Kelly-Lochbaum Vocal Tract
This may be the first instance of a sampled traveling-wave model of the vocal tract, as opposed to a lumped-parameter transmission-line model.
This sampled, bandlimited approach to digitization contrasts with the use of bilinear transforms as in wave digital filters; an advantage is that the frequency axis is not warped, but it is prone to aliasing when the parameters vary over time (or if nonlinearities are present).
In addition to the basic vocal tract model with side branch for the nasal tract, Cook included neck radiation (e.g.
ccrma.stanford.edu /~jos/pasp/Singing_Kelly_Lochbaum_Vocal_Tract.html   (693 words)

  
 Dunn's Electrical Vocal Tract   (Site not responding. Last check: 2007-10-17)
"By treating the vocal tract as a series of cylindrical sections, or acoustic lines, it is possible to use transmission line theory"...
A line with distributed constants is approximated through the use of 25 lumped sections, each representing a cylinder 0.5 cm long and 6 cm**2 in cross section.
Its position in the tract is changed by sliding the whole panel back and forth.
www.haskins.yale.edu /featured/heads/SIMULACRA/dunn.html   (313 words)

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