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Electroglottograph and microphone signals are examined of scale passages crossing the boundary between chest and middle registers in the female singing voice. From a protocol executed by professional classical singers, the examples are selected to illustrate differing approaches to the chest-middle transition, as well as to illuminate varying theories on the female middle register, specifically the question of 'mixing' the primary registers, chest and falsetto. The results suggest that the skillful tuning of the resonances of the vocal tract contributes more toward the pedagogical goal of smoothing the register transition than does a presumed mixing of the registers at the glottal source., ((c) 2005 S. Karger AG, Basel)

With careers that depend to a large extent on the amplitude and sonorous beauty of their voices, opera singers must pay special attention to high notes, where the wide spacing of the harmonics of the voice source intensifies the critical importance of the tuning of the resonances of the vocal tract. This study uses spectrum analysis to examine a large number of recordings of a particularly challenging high note for tenors, the final sustained B4-flat of the aria 'Celeste Aida' from Verdi's opera Aida. The resonance strategy most frequently found uses a markedly displaced second formant to create a dominant resonance at the frequency of the third harmonic, about 1,400 Hz. Other strategies and combinations of strategies are examined as well. Arguments concerning the validity of drawing conclusions from the acoustic signals available in commercial recordings are considered, and it is concluded that such recordings can contain valuable information on resonance strategies for those who aspire to sing similar high notes., ((c) 2005 S. Karger AG, Basel)

A new numerical model of the vocal folds is presented based on the well-known two-mass models of the vocal folds. The two-mass model is coupled to a model of glottal airflow based on the incompressible Navier-Stokes equations. Glottal waves are produced using different initial glottal gaps and different subglottal pressures. Fundamental frequency, glottal peak flow, and closed phase of the glottal waves have been compared with values known from the literature. The phonation threshold pressure was determined for different initial glottal gaps. The phonation threshold pressure obtained using the flow model with Navier-Stokes equations corresponds better to values determined in normal phonation than the phonation threshold pressure obtained using the flow model based on the Bernoulli equation. Using the Navier-Stokes equations, an increase of the subglottal pressure causes the fundamental frequency and the glottal peak flow to increase, whereas the fundamental frequency in the Bernoulli-based model does not change with increasing pressure.

A markedly smaller time constant distinguishes a chest-falsetto leap from the more usual execution of a sung interval by muscular adjustments in the length and tension of the vocal folds. The features of such a chest-falsetto leap are examined in detail with respect to F0, peak-to-peak amplitude of the vocal-fold contact area signal (EGG), and the closed quotient. A method is proposed to standardize and quantify this chest-falsetto leap in the characteristic leap interval (CLI), a measure of the separation between the natural registers in a given singing voice. The measure is applied to a varied group of experienced singers. Preliminary results include a suggested dimorphic pattern with respect to sex, with female voices exhibiting smaller CLIs and less individual diversity than male voices.

Sustained high notes, diminishing gradually from the loudest to the softest phonation within a maneuver called messa di voce, are examined in two contrasting professional tenor voices. Signals of the sound pressure level, electroglottograph, and mean esophageal pressure are recorded, and similar maneuvers by the same subjects are examined stroboscopically. The lyric voice is found to make a gradual diminuendo while maintaining nearly constant posture of the vocal tract together with a phase of complete closure in the glottal cycle. The robust voice, by contrast, passes abruptly from a production of high subglottal pressure and a high closed quotient to one of low pressure and incomplete closure, and the transition is marked by a sudden opening of the previously constricted laryngeal collar. It is proposed that the mode of soft voice production demonstrated by the robust voice be recognized as a distinct register of the singing voice.

This study explores resonance strategies used for the belting style and associated vocal fold vibratory patterns, for the vowels /e/, /a/, /i/, and /u/ on G4 and B4-flat. Acoustic spectra of belted vowels and their unoptimized, "speech-like" equivalents were compared. Vocal fold vibratory patterns were quantified using electroglottography. Results show that /a/ is inherently suitable for belting and requires no adjustment. For /e/, F2-H5 tuning was observed. For /i/, F1 was detuned from H1, enhancing also H2. For /u/, both F1 and F2 were raised to accomplish F2-H3 tuning. These results show that the loud, bright sound of the belting style is achieved by the implementation of resonance strategies that enhance higher harmonics. Electroglottography revealed that resonance strategies also result in raising the closed quotient (CQ) above 52%, an apparent threshold value for belting.

Singing not only requires good voluntary control over phonation and a musical ear, it also demands certain capacities of the voice source. These capacities include a desirable range of sound intensity and frequency, which can be measured and represented in a phonetogram. The influence of specific factors on voice capacities may be ascertained by the analysis of phonetograms. To determine the influence of the factors gender and voice training, phonetograms of 224 subjects, subdivided accordingly into four groups, were analyzed in two different ways. One is based on the rescaling of phonetograms, whereas the other derives analytic variables from the features' shape, area, and dynamic range. Analysis showed that, regarding gender, male subjects are able to produce softer phonations, whereas female subjects produced louder phonations at specific parts of their comparable frequency ranges. Trained subjects have a larger enclosed area of the phonetogram, which is primarily based on extended soft voice capabilities in both genders and the significantly larger frequency range in trained female subjects. The shape analysis, performed with Fourier Descriptors, revealed differences for the factors gender and training.

That singers under certain circumstances adjust the articulation of the vocal tract (formant tuning) to enhance acoustic output is both apparent from measurements and understood in theory. The precise effect of a formant on an approaching (retreating) harmonic as the latter varies in frequency during actual singing, however, is difficult to isolate. In this study variations in amplitude of radiated sound components as well as supraglottal and subglottal (esophageal) pressures accompanying the vibrato-related sweep of voice harmonics were used as a basis for estimating the effective center frequencies and bandwidths of the first and second formants.

For male singers in the western operatic tradition the upper part of the frequency range contains a series of pitches called passaggio, the transition between 'chest' and 'head' registers. Although there is no generally accepted objective definition of the distinction between 'head' and 'chest', the distinction is widely recognized among singers and voice teachers, as is the term 'cover', a technique often considered to be helpful in a proper execution of passaggio. On the basis of spectrographic, electroglottographic, and sub- and supraglottal pressure measurements on professional singers' 'correct' and 'incorrect' singing of passaggio, this study offers a definition of the 'chest'/'head' distinction.

There is a commonly perceived difference in the sound produced in the approximate range D4-D5 by female singers in the western opera and concert tradition, on the one hand, and certain other styles, including rock, pop, folk, and some Broadway musicals, on the other. The term "belting" is sometimes used to refer to at least one approach to such "nonclassical" singing. In this study, based on spectrographic, electroglottographic, and sub- and supraglottal pressure measurements on representative voices of the "operatic" and "nonclassical" tradition, acoustic and laryngeal differences between the two traditions are described, and an objective, specific definition of "belting" is offered.

The relation between the spatial configuration of the vocal tract as determined by magnetic resonance imaging (MRI) and the acoustical signal produced was investigated. A male subject carried out a set of phonatory tasks, comprising the utterance of the sustained vowels /i/ and /a/, each in a single articulation, and the vowel /epsilon/ with his larynx positioned variously on a vertical axis. Two- and three-dimensional measurements of the vocal tract were performed. The results of these measurements were used to calculate resonance frequencies, according to predictions from acoustical theory. Finally, calculated frequencies were compared with actually measured resonance frequencies in the audio signal. We found a strong relation between the acoustical signal produced and the spatial configuration for the first resonance frequencies of the articulations of the vowel /epsilon/, and first two resonance frequencies of the vowels /a/ and /i/. The capability to determine accurately vocal tract dimensions is a major advantage of this imaging technique.

An overview is given of the results of simultaneous measurements of mean air flow rate, mean subglottal pressure, and sound intensity in 45 test-persons and 64 voice patients. From these values the efficiency of voice production is calculated. The measuring procedure as well as the use of data from test-persons as reference values is described. Comparing the results of voice patients with these reference values showed that the diagnostic usefulness of measuring aerodynamic data in voice production is generally low. Aerodynamic data from patients with slight adduction disturbances, however, lead to a better understanding of the pathophysiology in cases with an incomplete dorsal glottis closure and give directions to a more adequate therapy programme.

Laryngeal framework surgery for improving or changing the voice is a challenging development in phoniatric surgery. Basically two categories can be distinguished: (1) attempted medialization of the vocal fold, as for the treatment of paralytic dysphonias (arytenoid rotation technique and Isshiki's type I thyroplasty); (2) adjustment of the vocal fold's tension to produce changes in vocal pitch, as for the treatment of transsexuals or mutational dysphonia (cricothyroid approximation, Isshiki's type III thyroplasty and LeJeune's anterior commissure laryngoplasty). Both types of surgery are best performed with the patient under local anesthesia so that fine tuning of the voice is possible by monitoring the voice during the surgical procedure. The techniques of arytenoid rotation and Isshiki's type I thyroplasty are described in detail and the result of a combination of these procedures is illustrated by a case history of an aphonic patient with unilateral vagus nerve paralysis and subsequent severe incomplete glottal closure during phonation. In addition, the results achieved in several other patients are presented. Our current experience with laryngoplastic surgery and its variations is such that endolaryngeal Teflon or collagen injections are no longer used in our department. To date, we have seen no complications from the laryngoplasties and the voice results have been excellent.

Patients with organic or functional voice disorders show a considerable agreement between the individual aerodynamic phonatory pattern and the appearances on indirect laryngoscopy during phonation. Both groups were characterized by incomplete dorsal glottic closure. The aerodynamic data (subglottal pressure and transglottal flow) and the laryngeal efficiency support a pathophysiological explanation of abnormal and breathy voicing. Division of the transglottal flow into modulated and unmodulated parts explains how a better voice will be obtained with equal or lower flow values by relaxation of the musculature. The decreased tension of the muscles also produces phonation with a lower subglottal pressure. The onset of fatigue is therefore delayed. It is concluded that mild adduction disorders are neither organic nor functional disorders. Rather there is a continuum of organic alterations with different laryngeal functional disturbances.

Using high-frequency miniature pressure transducers, direct measurements of sub- and supra-glottal pressure are taken on two sopranos singing high notes, in a range where F1 is close to F0. When the peak in supraglottal pressure occurs well into the open phase of the glottal cycle, the instantaneous transglottal pressure approaches zero. When this peak occurs later in one of the subjects as a feature of the vibrato modulation, the transglottal pressure even drops appreciably below zero. The implications of these findings for the glottal volume velocity waveform, as well as for the singer's experience of the second "passaggio" point, are discussed.