Acoustic Properties of the Voice Source and the Vocal Tract: Are They Perceptually Independent?

The sound quality of singing is determined by three basic factors—the air pressure under the vocal folds (or the subglottal pressure), the mechanical properties of the vocal folds, and the resonance properties of the vocal tract. Subglottal pressure is controlled by the respiratory apparatus. It regulates vocal loudness and is varied with pitch in singing. Together with the mechanical properties of the folds, which are controlled by laryngeal muscles, it has a decisive influence on vocal fold vibrationswhich convert the tracheal airstream to a pulsating airflow, the voice source. The voice source determines pitch, vibrato, and register, and also the overall slope of the spectrum. The sound of the voice source is filtered by the resonances of the vocal tract, or the formants, of which the two lowest determine the vowel quality and the higher ones the personal voice quality. Timing is crucial for creating emotional expressivity; it uses an acoustic code that shows striking similarities to that used in speech. The perceived loudness of a vowel sound seems more closely related to the subglottal pressure with which it was produced than with the acoustical sound level. Some investigations of acoustical correlates of tone placement and variation of larynx height are described, as are properties that affect the perceived naturalness of synthesized singing. Finally, subglottal pressure, voice source, and formant-frequency characteristics of some non-classical styles of singing are discussed.

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Monitoring Cognitive Workload Using Vocal Tract and Voice Source Features

Periodica Polytechnica Electrical Engineering and Computer Science ◽

10.3311/ppee.10414 ◽

2017 ◽

Vol 61 (4) ◽

pp. 297 ◽

Cited By ~ 3

Author(s):

Eydis Huld Magnusdottir ◽

Michal Borsky ◽

Manuela Meier ◽

Kamilla Johannsdottir ◽

Jon Gudnason

Keyword(s):

Speech Signal ◽

Vocal Tract ◽

Memory Span ◽

Svm Classifier ◽

Cognitive Workload ◽

Voice Source ◽

Human Decision ◽

Rest Time ◽

The Voice ◽

Stroop Tasks

Monitoring cognitive workload from speech signals has received much attention from researchers in the past few years as it has the potential to improve performance and fidelity in human decision making. The bulk of the research has focused on classifying speech from talkers participating in cognitive workload experiments using simple reading tasks, memory span tests and the Stroop test, typically into three levels of low, medium and high cognitive workload. This study focuses on using parameters extracted from the vocal tract and the voice source components of the speech signal for cognitive workload monitoring. The experiment used in this study contains 98 participants, the levels were obtained by using a reading task and three Stroop tasks which were randomly ordered for each participant and an adequate rest time was used inbetween tasks to mitigate the effect of cognitive workload from one task affecting the subsequent one. Vocal tract features were obtained from the first three formants and voice source features were extracted using signal analysis on the inverse filtered speech signal. The results show that on their own, the vocal tract features outperform the voice source features. The MCR of 33.92% ± 1.05 was achieved with a SVM classifier. A weighted combination of vocal tract and voice source features classified with SWM classifier fused at the output level achieved the lowest MCR of 32.5%.

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Acoustic interactions of the voice source with the lower vocal tract

The Journal of the Acoustical Society of America ◽

10.1121/1.418246 ◽

1997 ◽

Vol 101 (4) ◽

pp. 2234-2243 ◽

Cited By ~ 178

Author(s):

Ingo R. Titze ◽

Brad H. Story

Keyword(s):

Vocal Tract ◽

Voice Source ◽

The Voice

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Une nouvelle méthode de mesure de la fonction d'aire du conduit vocal : cas des voyelles

Canadian Journal of Physics ◽

10.1139/p05-026 ◽

2005 ◽

Vol 83 (7) ◽

pp. 721-737

Author(s):

H Teffahi ◽

B Guerin ◽

A Djeradi

Keyword(s):

Measurement Method ◽

Cross Correlation ◽

Sound Production ◽

Linear Prediction ◽

Vocal Tract ◽

Random Sequence ◽

Speech Sound ◽

Acoustic Properties ◽

External Excitation ◽

White Noise Excitation

Knowledge of vocal tract area functions is important for the understanding of phenomena occurring during speech production. We present here a new measurement method based on the external excitation of the vocal tract with a known pseudo-random sequence, where the area function is obtained by a linear prediction analysis applied to the cross-correlation between the sequence and the signal measured at the lips. The advantages of this method over methods based on sweep-tones or white noise excitation are (1) a much shorter measurement time (about 100 ms) and (2) the possibility of speech sound production during the measurement. This method has been checked against classical methods through systematic comparisons on a small corpus of vowels. Moreover, it has been verified that simultaneous speech sound production does not perturb significantly the measurements. This method should thus be a very helpful tool for the investigation of the acoustic properties of the vocal tract in various cases for vowels.

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Kinematics of birdsong: functional correlation of cranial movements and acoustic features in sparrows

Journal of Experimental Biology ◽

10.1242/jeb.182.1.147 ◽

1993 ◽

Vol 182 (1) ◽

pp. 147-171 ◽

Cited By ~ 10

Author(s):

M. W. Westneat ◽

J. H. Long ◽

W. Hoese ◽

S. Nowicki

Keyword(s):

Vocal Tract ◽

Active Role ◽

Acoustic Properties ◽

Zonotrichia Albicollis ◽

Low Frequencies ◽

Acoustic Frequency ◽

Mean Frequency ◽

Singing Behavior ◽

Resonance Properties ◽

Melospiza Georgiana

The movements of the head and beak of songbirds may play a functional role in vocal production by influencing the acoustic properties of songs. We investigated this possibility by synchronously measuring the acoustic frequency and amplitude and the kinematics (beak gape and head angle) of singing behavior in the white-throated sparrow (Zonotrichia albicollis) and the swamp sparrow (Melospiza georgiana). These birds are closely related emberizine sparrows, but their songs differ radically in frequency and amplitude structure. We found that the acoustic frequencies of notes in a song have a consistent, positive correlation with beak gape in both species. Beak gape increased significantly with increasing frequency during the first two notes in Z. albicollis song, with a mean frequency for note 1 of 3 kHz corresponding to a gape of 0.4 cm (a 15 degrees gape angle) and a mean frequency for note 2 of 4 kHz corresponding to a gape of 0.7 cm (a 30 degrees gape angle). The relationship between gape and frequency for the upswept third note in Z. albicollis also was significant. In M. georgiana, low frequencies of 3 kHz corresponding to beak gapes of 0.2-0.3 cm (a 10–15 degrees break angle), whereas frequencies of 7–8 kHz were associated with flaring of the beak to over 1 cm (a beak angle greater than 50 degrees). Beak gape and song amplitude are poorly correlated in both species. We conclude that cranial kinematics, particularly beak movements, influence the resonance properties of the vocal tract by varying its physical dimensions and thus play an active role in the production of birdsong.

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Physiology and its Impact on the Performance of Singing

The Oxford Handbook of Singing ◽

10.1093/oxfordhb/9780199660773.013.23 ◽

2015 ◽

pp. 66-84

Author(s):

Filipa M. B. Lã ◽

Brian P. Gill

Keyword(s):

Vocal Tract ◽

Teaching Method ◽

Vocal Technique ◽

Voice Source ◽

Advantages And Disadvantages ◽

Physiological Processes ◽

Subglottal Pressure ◽

Source Signal ◽

Frequency Components ◽

Singing Performance

Singing performance is highly competitive; thus, finding strategies to accelerate the acquisition of knowledge that results in an efficient and effective vocal technique is of the utmost importance. There are many ways in which a singer may acquire an efficient and effective vocal technique, which can be based on the physiological processes of voice production. This chapter explores these processes within the context of singing performance. The authors examine three major aspects of singing: 1) efficient control of breathing, such that optimal airflow and subglottal pressure are available as needed, for a given frequency and intensity; 2) maximized laryngeal coordination, so that the voice source signal contains all the necessary frequency components for the desired tone; and 3) the modulation of the source signal by subtle shaping of the vocal tract. The advantages and disadvantages of various pedagogical methods are discussed, including breath management, known as appoggio, and different resonant strategies. The authors advocate for a scientifically-grounded teaching method, which allows for physiological differences between individuals, genders, and voice classifications.

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