Register Transitions Research Articles

Register transitions in an in vivo canine model as a function of intrinsic laryngeal muscle stimulation, fundamental frequency, and sound pressure level.

Phonatory instabilities and involuntary register transitions can occur during singing. However, little is known regarding the mechanisms which govern such transitions. To investigate this phenomenon, we systematically varied laryngeal muscle activation and airflow in an in vivo canine larynx model during phonation. We calculated voice range profiles showing average nerve activations for all combinations of fundamental frequency (F0) and sound pressure level (SPL). Further, we determined closed-quotient (CQ) and minimum-posterior-area (MPA) based on high-speed video recordings. While different combinations of muscle activation favored different combinations of F0 and SPL, in the investigated larynx there was a consistent region of instability at about 400 Hz which essentially precluded phonation. An explanation for this region may be a larynx specific coupling between sound source and subglottal tract or an effect based purely on larynx morphology. Register transitions crossed this region, with different combinations of cricothyroid and thyroarytenoid muscle (TA) activation stabilizing higher or lower neighboring frequencies. Observed patterns in CQ and MPA dependent on TA activation reproduced patterns found in singers in previous work. Lack of control of TA stimulation may result in phonation instabilities, and enhanced control of TA stimulation may help to avoid involuntary register transitions, especially in the singing voice.

Effects of a Straw Phonation on Acoustic and Self-Reported Measures of Adolescent Female Singers: A Pilot Study

ABSTRACT Characteristics of adolescent female voice change include breathiness, inconsistent pitch, “cracks,” abrupt register transitions, vocal range changes, and decreased stamina. Researchers have found that semi-occluded vocal tract exercises (e.g. straw phonation) can assist with such difficulties with other varied populations, facilitating glottal closure, decreasing breathiness, and encouraging easier voicing. Therefore, the purpose of this investigation was to measure the effects of straw phonation (experimental) compared to “ah” vowel (control) warm-ups on acoustic and self-reported measures of seventh-grade female-identifying singers. We calculated each participant’s Acoustic Voice Quality Index (AVQI) prior to and after a 4–5-minute straw phonation (n = 6) or unoccluded “ah” vowel (n = 6) warm-up. Results indicated robust improvement in AVQI scores after both warm-ups, with a trend toward more acoustic improvement after straw phonation (5 improved, M = 0.48, compared to 4, M = 0.35). All participants self-reported that their respective voicing helped them to be more warmed up, but the effect was statistically much larger in the straw group (7.23 to 5.00, 10-point scale). Some participants self-reported that straw phonation was more effective than their typical warm-up. These results may indicate more robust benefits from straw phonation, which could facilitate increased motivation during a difficult transition.

On the Pedagogical Priorities of Teachers-vocalists of the Initial Period of Activity of the Saratov Conservatory

The object of this study is the initial period of activity of the Saratov Conservatory; the subject can be called the pedagogical priorities of vocal teachers of this period under consideration. In the article, based on rare archival data, surviving printed evidence, and student memoirs, an attempt is made to restore the pedagogical priorities of the most famous and influential in the musical circles of Moscow and St. Petersburg, active participants in concert events of the Imperial Russian Musical Society: Mikhail Efimovich Medvedev - the first performer of the role of Lensky in the opera P. I. Tchaikovsky's "Eugene Onegin" and Alevtina Mikhailovna Paskhalova, who embodied the image of the Snow Maiden in the opera of the same name by N. A. Rimsky-Korsakov. The scientific novelty of the study includes the fact that the author identifies and for the first time introduces into scientific circulation data on the pedagogical priorities of the most prominent vocal teachers who have made a significant contribution to improving the educational process of the department of academic singing. It is revealed that the pedagogical priorities of M. E. Medvedev and A. M. Paskhalova include: a fairly low type of breathing, increased attention to developing a sense of support for sound, a cautious attitude towards the development of the full range of the voice, the development of clear diction, evenness of sound production, smoothness of register transitions; soft sound attack; the ability to qualitatively vocalize various dynamic gradations of sound; the use of the “concentric” teaching method in the pedagogical process, increased attention to the education of the emotional and dramatic component of the performer’s personality. The analysis also showed that the features that distinguish the pedagogical views of the professors of the initial period of the Saratov Conservatory include the use of the repertoire of Russian composers in class work with a beginning singer.

Evaluation of the Supraglottic and Subglottic Activities Including Acoustic Assessment of the Opera-Chant Singers

Opera and chant singers learn to effectively use aerodynamic components by breathing exercises during their education. Aerodynamic components, including subglottic air pressure and airflow, deteriorate in voice disorders. This study aimed to evaluate the changes in aerodynamic parameters and supraglottic structures of men and women with different vocal registers who are in an opera and chant education program. Vocal acoustic characteristics, aerodynamic components, and supraglottic structures were evaluated in 40 opera and chant art branch students. The majority of female students were sopranos, and the male students were baritone or tenor vocalists. The acoustic analyses revealed that the mean fundamental frequency was 152.33 Hz in the males and 218.77 Hz in the females. The estimated mean subglottal pressures were similar in females (14.99 cmH2O) and in males (14.48 cmH2O). Estimated mean airflow rates were also similar in both groups. The supraglottic structure compression analyses revealed partial anterior-posterior compressions in 2 tenors and 2 sopranos, and false vocal fold compression in 2 sopranos. Opera music is sung in high-pitched sounds. Attempts to sing high-pitched notes and frequently using register transitions overstrain the vocal structures. This intense muscular effort eventually traumatizes the vocal structures and causes supraglottic activity.

歌声の非線形科学 : 分岐現象として捉えた声区転換のメカニズム( 歌声の科学)

歌声の非線形科学 : 分岐現象として捉えた声区転換のメカニズム( 歌声の科学)

Laryngeal evidence for the first and second passaggio in professionally trained sopranos.

IntroductionDue to a lack of empirical data, the current understanding of the laryngeal mechanics in the passaggio regions (i.e., the fundamental frequency ranges where vocal registration events usually occur) of the female singing voice is still limited.Material and methodsIn this study the first and second passaggio regions of 10 professionally trained female classical soprano singers were analyzed. The sopranos performed pitch glides from A3 (ƒo = 220 Hz) to A4 (ƒo = 440 Hz) and from A4 (ƒo = 440 Hz) to A5 (ƒo = 880 Hz) on the vowel [iː]. Vocal fold vibration was assessed with trans-nasal high speed videoendoscopy at 20,000 fps, complemented by simultaneous electroglottographic (EGG) and acoustic recordings. Register breaks were perceptually rated by 12 voice experts. Voice stability was documented with the EGG-based sample entropy. Glottal opening and closing patterns during the passaggi were analyzed, supplemented with open quotient data extracted from the glottal area waveform.ResultsIn both the first and the second passaggio, variations of vocal fold vibration patterns were found. Four distinct patterns emerged: smooth transitions with either increasing or decreasing durations of glottal closure, abrupt register transitions, and intermediate loss of vocal fold contact. Audible register transitions (in both the first and second passaggi) generally coincided with higher sample entropy values and higher open quotient variance through the respective passaggi.ConclusionsNoteworthy vocal fold oscillatory registration events occur in both the first and the second passaggio even in professional sopranos. The respective transitions are hypothesized to be caused by either (a) a change of laryngeal biomechanical properties; or by (b) vocal tract resonance effects, constituting level 2 source-filter interactions.

Vocal and Neural Responses to Unexpected Changes in Voice Pitch Auditory Feedback During Register Transitions

It is known that singers are able to control their voice to maintain a relatively constant vocal quality while transitioning between vocal registers; however, the neural mechanisms underlying this effect are not understood. It was hypothesized that greater attention to the acoustical feedback of the voice and increased control of the vocal musculature during register transitions compared with singing within a register would be represented as neurological differences in event-related potentials. Nine singers sang musical notes at the high end of the modal register (the boundary between the modal and the head/falsetto registers) and at the low end (the boundary between the modal and the fry/pulse registers). While singing, the pitch of the voice auditory feedback was unexpectedly shifted either into the adjacent register ("toward" the register boundary) or within the modal register ("away from" the boundary). Singers were instructed to maintain a constant pitch and ignore any changes to their voice feedback. Vocal response latencies and magnitude of the accompanying N1 and P2 event-related potentials were greatest at the lower (modal-to-fry) boundary when the pitch shift carried the subjects' voices into the fry register as opposed to remaining within the modal register. These findings suggest that when a singer lowers the pitch of his or her voice such that it enters the fry register from the modal register, there is increased sensory-motor control of the voice, reflected as increased magnitude of the neural potentials to help minimize qualitative changes in the voice.

High-Speed Imaging Analysis of Register Transitions in Classically and Jazz-Trained Male Voices

Background: Little data are available concerning register functions in different styles of singing such as classically or jazz-trained voices. Differences between registers seem to be much more audible in jazz singing than classical singing, and so we hypothesized that classically trained singers exhibit a smoother register transition, stemming from more regular vocal fold oscillation patterns. Methods: High-speed digital imaging (HSDI) was used for 19 male singers (10 jazz-trained singers, 9 classically trained) who performed a glissando from modal to falsetto register across the register transition. Vocal fold oscillation patterns were analyzed in terms of different parameters of regularity such as relative average perturbation (RAP), correlation dimension (D2) and shimmer. Results: HSDI observations showed more regular vocal fold oscillation patterns during the register transition for the classically trained singers. Additionally, the RAP and D2 values were generally lower and more consistent for the classically trained singers compared to the jazz singers. However, intergroup comparisons showed no statistically significant differences. Conclusion: Some of our results may support the hypothesis that classically trained singers exhibit a smoother register transition from modal to falsetto register.

High-speed imaging using rigid laryngoscopy for the analysis of register transitions in professional operatic tenors

Introduction. Vocal fold oscillation patterns in tenors singing at high pitches (stage voice above the passaggio) are not yet understood in detail. Materials and methods. Nine professional opera tenors performed a transition from modal register (220 Hz) to falsetto or stage voice above the passaggio (440 Hz) on an /i/ vowel. High-speed digital imaging was performed using a rigid laryngoscopic system with a frame rate of 4,000 frames per second. Results. During the transition to stage voice above the passaggio seven out of nine tenors exhibited a strong retraction of the epiglottis with rising F0, which prevented further analysis of vocal fold oscillations. During transitions to falsetto many supraglottic modifications were also observed. Conclusion. Tenor stage voice above the passaggio seems to be typically associated with retraction of the epiglottis for the vowel /i/ thus preventing examination of vocal fold oscillations using rigid laryngoscopy.

On transition between voice registers: Data from high-speed laryngeal videoendoscopy

How specific aspects of vocal fold vibration alter voice register has long been a subject of interest. Transitions between vocal registers are often studied using dynamic vocal fold models and electroglottographic signals. Although laryngeal high-speed videoendoscopy has also been applied to study steady-state voice registers, there has been little such investigation on the transitions between registers. In this study, we examined voice register transitions using phonations in which vocal qualities varied continuously in fundamental frequency (F0), loudness, or voice quality (from breathy to pressed). Glottal area measures {open quotient and alternating-current to open quotient ratios [Chen et al., JASA 133, 1656–1666 (2013)]} and acoustic measures (F0, energy, and H1-H2) were studied using simultaneously collected laryngeal high-speed videoendoscopy and audio recordings from 15 subjects. The video recordings were collected transorally at 10 000 frames per second. Glottal area waveforms were extracted using GlotAnTools (Version 5) [Erlangen, Germany], and acoustic measures were gathered using VoiceSauce software and analysis-by-synthesis. Glottal area measures were compared to acoustic measures and their relationships to voice register transitions were explored.

Acoustic and physiologic measures of register transitions sung by females

The purpose of this study was to examine the physiological and acoustical adjustments made by trained female singers to transition across vocal registers when singing a chord triad. Ten female singers participated in this study. A microphone was placed 30 cm from the corner of the subjects mouth and EGG electrodes were positioned over their thyroid laminae. Audio and EGG signals were channeled to Voce Vista Pro software. Each singer was presented the starting pitch of A3 or 220 Hz, by the experimenter and directed to sing a chord triad using an [a:] vowel. Each triad was sung in a single breath at an andante tempo. The EGG measurements included the closing quotient (CQ) and the FFT spectrum measurements include the harmonic number, frequency, and amplitude of the harmonic with the greatest amplitude. Four singers lowered CQ, two raised CQ, and four maintained a steady CQ when changing vocal register. The frequencies and amplitudes of the peak harmonic remained fairly steady across the register shift. These changes indicated that the singers were tracking their vocal tract resonance to their CQ. The more trained singers used the third harmonic in their chest register and the second harmonic in middle register.

Perturbation of Voice Signals in Register Transitions on Sustained Frequency in Professional Tenors

Vocal register transitions in the passaggio region remain an unclarified field in classically trained male singers. We examined the acoustic and electroglottographic signals of seven tenors' transitions from voix mixte to falsetto on a sustained pitch F4 (349Hz) on the vowels /a, e, i, o, u, and æ/. It was found that in many of the tested subjects, register transitions between voix mixte and falsetto were performed very continuously without clear register transition events. However, an increase of frequency and amplitude perturbation (jitter, relative average perturbation, and shimmer) was observed during register transitions. These data suggest that professional tenors are able to avoid sudden registration events frequently observed in untrained voices.

Passaggio in the Professional Tenor Voice—Evaluation of Perturbation Measures

Vocal stability throughout the passaggio region in professional singers is an unclarified area of research. The acoustic and electroglottographic signals of ascending and descending frequency transitions from 220 to 440 Hz (and vice versa) on the vowels /a, e, i, o, u, æ/ were analyzed in eight professional tenors. The frequency transitions were accompanied by shifts in register conditions, from modal to unmodulated naïve falsetto and modal to voix mixte (and vice versa). For ascending tasks, it was found that frequency perturbation values (jitter and relative average perturbation) were higher for the frequency transition and upper frequency produced in naïve falsetto or voix mixte compared with lower frequency produced in modal register. No such higher values were found for descending tasks. Shimmer was increased during frequency transitions between modal and naïve falsetto. The electroglottographic contact quotient showed a positive correlation with the sound pressure level for the modal register and voix mixte but not for the naïve falsetto. In our study, ascending tasks, including register transitions, are different from descending tasks with regard to frequency perturbation in professional tenors.

Biomechanical modeling of register transitions and the role of vocal tract resonators

Biomechanical modeling and bifurcation theory are applied to study phonation onset and register transition. A four-mass body-cover model with a smooth geometry is introduced to reproduce characteristic features of chest and falsetto registers. Sub- and supraglottal resonances are modeled using a wave-reflection model. Simulations for increasing and decreasing subglottal pressure reveal that the phonation onset exhibits amplitude jumps and hysteresis referring to a subcritical Hopf bifurcation. The onset pressure is reduced due to vocal tract resonances. Hysteresis is observed also for the voice breaks at the chest-falsetto transition. Varying the length of the subglottal resonator has only minor effects on this register transition. Contrarily, supraglottal resonances have a strong effect on the pitch, at which the chest-falsetto transition is found. Experiment of glissando singing shows that the supraglottis has indeed an influence on the register transition.

High-Speed Imaging and Electroglottography Measurements of the Open Quotient in Untrained Male Voices' Register Transitions

Vocal fold oscillation patterns in vocal register transitions are still unclarified. The vocal fold oscillations and the open quotient were analyzed with high-speed digital imaging (HSDI) and electroglottography (EGG) in 18 male untrained subjects singing a glissando from modal to the falsetto register. Results reveal that the open quotient changed with register in both HSDI and EGG. The in-class correlations for different HSDI and EGG determinations of the open quotient were high. However, we found only weak interclass correlations between both methods. In 10 subjects, irregularities of vocal fold vibration occurred during the register transition. Our results confirm previous observations that falsetto register is associated with a higher open quotient compared with modal register. These data suggest furthermore that irregularities typically observed in audio and electroglottographic signals during register transitions are caused by irregularities in vocal fold vibration.

Vocal Tract in Female Registers—A Dynamic Real-Time MRI Study

The area of vocal registers is still unclarified. In a previous investigation, dynamic real-time magnetic resonance imaging (MRI), which is able to produce up to 10 frames per second, was successfully applied for examinations of vocal tract modifications in register transitions in male singers. In the present study, the same MRI technique was used to study vocal tract shapes during four professional young sopranos' lower and upper register transitions. The subjects were asked to sing a scale on the vowel /a/ across their transitions. The transitions were acoustically identified by four raters. In neither of these transitions, clear vocal tract changes could be ascertained. However, substantial changes, that is, widening of the lips, opening of the jaw, elevation of the tongue dorsum, and continuous widening of the pharynx, were observed when the singers reached fundamental frequencies that were close to the frequency of the first formant of the vowel sung. These findings suggest that in these subjects register transition was not primarily the result of modifications of the vocal tract.

Not just sound: Supplementing the voice range profile with the singer's own perceptions of vocal challenges

A commercial phonetograph was complemented with a response button, such that presses resulted in marked regions in the voice range profile (VRP). This study reports the VRP data of 16 healthy female professionally trained singers (7 mezzo-sopranos and 9 sopranos). Subjects pressed the button to indicate sensations of vocal instability or reduced control during phonation. Each press thereby marked potential areas of difficulty. A method is presented to quantify the consistency of button use for repeated tasks. The pattern of button presses was significantly consistent within subjects. As expected, the singers pressed at the extremes of VRP contours as well as at register transitions. These results and the potential of the method for the assessment of vocal problems of singers are discussed.

Bifurcations and chaos in register transitions of excised larynx experiments

Experimental data from an excised larynx are analyzed in the light of nonlinear dynamics. The excised larynx provides an experimental framework that enables artificial control and direct observation of the vocal fold vibrations. Of particular interest in this experiment is the coexistence of two distinct vibration patterns, which closely resemble chest and falsetto registers of the human voice. Abrupt transitions between the two registers are typically accompanied by irregular vibrations. Two approaches are presented for the modeling of the excised larynx experiment; one is the nonlinear predictive modeling of the experimental time series and the other is the biomechanical modeling (three-mass model) that takes into account basic mechanisms of the vocal fold vibrations. The two approaches show that the chest and falsetto vibrations correspond to two coexisting limit cycles, which jump to each other with a change in the bifurcation parameter. Irregular vibrations observed at the register jumps are due to chaos that exists near the two limit cycles. This provides an alternative mechanism to generate chaotic vibrations in excised larynx experiment, which is different from the conventionally known mechanisms such as strong asymmetry between the left and right vocal folds or excessively high subglottal pressure.

Comparison of biomechanical modeling of register transitions and voice instabilities with excised larynx experiments

Voice instabilities were studied using excised human larynx experiments and biomechanical modeling. With a controlled elongation of the vocal folds, the experiments showed registers with chest-like and falsetto-like vibrations. Observed instabilities included abrupt jumps between the two registers exhibiting hysteresis, aphonic episodes, subharmonics, and chaos near the register transitions. In order to model these phenomena, a three-mass model was constructed by adding a third mass on top of the simplified two-mass model. Simulation studies showed that the three-mass model can vibrate in both chest-like and falsetto-like patterns. Variation of tension parameters which mimic activities of laryngeal muscles could induce transitions between both registers. For reduced prephonatory areas and damping constants, extended coexistence of chest and falsetto registers was found, in agreement with experimental data. Subharmonics and deterministic chaos were observed close to transitions between the registers. It is concluded that the abrupt changes between chest and falsetto registers can be understood as shifts in dominance of eigenmodes of the vocal folds.

An Investigation of a Modal-Falsetto Register Transition Hypothesis Using Helox Gas

This study concerned the effect of the first subglottal formant (F 1′) on the modal-falsetto register transition in males and females. Phonations using air and a helium-oxygen mixture (helox) were used in a comparative study to tease apart possible acoustic and myoelastic contributions to involuntary register transitions. Recordings of the first subglottal formant and its accompanying bandwidths, and the lower and upper shift point marking the outer boundaries of abrupt register transitions, were obtained via a neck-mounted accelerometer, and analyzed using spectrograms and power spectra on a K-5500 Sona-Graph. The four subjects had their hearing masked bilaterally with speech level noise to increase the likelihood of involuntary register transition via minimized auditory feedback. In three of the four test subjects registration was surmised to be primarily a laryngeal event, as evidenced by the similar frequency dependency of voice breaks in both air and helox. It may be hypothesized that subglottal resonance influenced register transition in the fourth subject, as voice breaks rose with helox-induced phonation; however, this result did not reach statistical significance. Therefore, in this experiment subglottal resonance was not found to have a significant influence on register transition as originally hypothesized.