Resonance Tuning in Three Girl Choristers

OBJECTIVE

The phenomenon of resonance tuning, whereby a singer modifies the shape of their vocal tract to increase the acoustic power output, is commonly exploited across large pitch ranges by professional sopranos and has been observed to a lesser degree in nonexpert adult singers. This study considers the employment of two common resonance tuning techniques in experienced child singers; tuning the first vocal tract resonance to the fundamental (R₁: f_o) and tuning the second resonance to the second harmonic (R₂:2 f_o).

METHODS

Wide-band excitation at the subject's mouth during singing was used to measure the vocal tract resonances of three girl choristers, and vowel formant values in speech were extracted from samples of spoken text. Measured resonance values were cross-referenced with first and second harmonics for sung vowels across the subjects' ranges to identify the resonance tuning techniques employed, and these results were compared with those previously observed by others in professional adult classical singers.

RESULTS AND CONCLUSIONS

There was clear evidence that the subjects employed resonance tuning techniques comparable with the strategies used by adult singers. The protocol and results presented here pave the way for further studies exploring the development of resonance tuning techniques in young soprano voices, with the potential to impact on approaches to classical singing training in the future.

Interactive Augmentation of Voice Quality and Reduction of Breath Airflow in the Soprano Voice

In 1985, at a conference sponsored by the National Institutes of Health, Martin Rothenberg first described a form of nonlinear source-tract acoustic interaction mechanism by which some sopranos, singing in their high range, can use to reduce the total airflow, to allow holding the note longer, and simultaneously enrich the quality of the voice, without straining the voice. (M. Rothenberg, "Source-Tract Acoustic Interaction in the Soprano Voice and Implications for Vocal Efficiency," Fourth International Conference on Vocal Fold Physiology, New Haven, Connecticut, June 3-6, 1985.) In this paper, we describe additional evidence for this type of nonlinear source-tract interaction in some soprano singing and describe an analogous interaction phenomenon in communication engineering. We also present some implications for voice research and pedagogy.

Semioccluded Vocal Tract Exercises: Changes in Laryngeal and Pharyngeal Activity During Stroboscopy

OBJECTIVE

The purpose of this study was to compare the changes in laryngeal activity from baseline during three different semioccluded vocal tract exercises (SOVTs).

STUDY DESIGN

This is a prospective case-series study.

METHODS

Transnasal stroboscopy was performed while four singers performed three SOVTs (straw phonation, lip trill, and tongue trill) to evaluate laryngeal changes during the execution of SOVTs. Evaluations using a modified Stroboscopy Evaluation Rating Form captured the following parameters: amplitude of vocal fold movement, mucosal wave, phase closure, glottal closure, anterior-posterior vocal tract constrictions, medial-lateral vocal tract constrictions, laryngeal ascension, and pharyngeal constriction during a pitch glide.

RESULTS

The parameters that changed from baseline, as well as the direction and magnitude of change that occurred across SOVTs, varied within and between each subject. All the singers benefited from at least one SOVT, but no single SOVT benefited all four singers.

CONCLUSIONS

Although SOVTs result in endoscopic and stroboscopic changes that might be considered beneficial, the results indicate marked variability across SOVTs and singers in terms of the laryngeal and pharyngeal adjustments induced by the exercises. Singing teachers and Speech Language Pathologists (SLPs) may need to more carefully assess the impact of specific SOVTs when deciding which one(s) to prescribe as a teaching or therapeutic exercise.

The Measurement of Airflow Using Singing Helmet That Allows Free Movement of the Jaw

OBJECTIVES

Airflow measurement is a useful method of evaluating laryngeal physiology. We introduce a noninvasive device that measures airflow without restricting jaw movement or requiring phonation into a mouthpiece, thus facilitating measurement during singing and connected speech.

STUDY DESIGN

Validation and human subject trials were conducted. Airflow measurements were obtained from 16 male and 16 female subjects during singing, speech, and constant vowel production tasks.

METHODS

A similar helmet was designed by Stevens and Mead in 1968. The new device validity was evaluated by comparing the measured volume of air to a known volume of administered air using a calibration syringe. Subjects were asked to voice sustained vowels at low, medium, and high vocal intensity, read two sentences at a conversational volume, and perform different singing exercises while airflow was recorded.

RESULTS

The device accurately and reliably measured airflow with mean airflow values falling within previously published ranges. There was an experimentally determined response time of 0.173 ± 0.014 seconds. Subjects were able to comfortably perform speech and singing exercises. Male subjects had higher airflow for all sustained vowels (P < 0.05). Airflow was higher for abduction rather than adduction sentences (P < 0.05).

CONCLUSIONS

No other portable device has been shown to measure airflow during singing and speech while allowing for free movement of the jaw. This device provides a more natural environment to measure airflow that could be used to help evaluate laryngeal function and aid in singing training.

Glottal Adduction and Subglottal Pressure in Singing

Previous research suggests that independent variation of vocal loudness and glottal configuration (type and degree of vocal fold adduction) does not occur in untrained speech production. This study investigated whether these factors can be varied independently in trained singing and how subglottal pressure is related to average glottal airflow, voice source properties, and sound level under these conditions. A classically trained baritone produced sustained phonations on the endoscopic vowel [i:] at pitch D4 (approximately 294 Hz), exclusively varying either (a) vocal register; (b) phonation type (from "breathy" to "pressed" via cartilaginous adduction); or (c) vocal loudness, while keeping the others constant. Phonation was documented by simultaneous recording of videokymographic, electroglottographic, airflow and voice source data, and by percutaneous measurement of relative subglottal pressure. Register shifts were clearly marked in the electroglottographic wavegram display. Compared with chest register, falsetto was produced with greater pulse amplitude of the glottal flow, H1-H2, mean airflow, and with lower maximum flow declination rate (MFDR), subglottal pressure, and sound pressure. Shifts of phonation type (breathy/flow/neutral/pressed) induced comparable systematic changes. Increase of vocal loudness resulted in increased subglottal pressure, average flow, sound pressure, MFDR, glottal flow pulse amplitude, and H1-H2. When changing either vocal register or phonation type, subglottal pressure and mean airflow showed an inverse relationship, that is, variation of glottal flow resistance. The direct relation between subglottal pressure and airflow when varying only vocal loudness demonstrated independent control of vocal loudness and glottal configuration. Achieving such independent control of phonatory control parameters would be an important target in vocal pedagogy and in voice therapy.

Performing Lieder: Expert Perspectives and Comparison of Vibrato and Singer's Formant With Opera Singers

This article reports three studies about performance of lieder, and in particular in comparison with opera performance. In study 1, 21 participants with experience in music performance and teaching completed a survey concerning various characteristics of lieder performance. The results showed that there was consensus between the literature and the assessment of an expert panel-that a "natural" and "unoperatic" vibrato was favored, and that diction, text, and variation of tone are all important aspects of lieder performance. Two acoustic analyses were conducted to investigate genre-specific differences of the singer's formant and vibrato parameters. The first analysis (study 2) used 18 single quasi-unaccompanied notes from commercial recordings of two lieder, and, for comparison, 20 single unaccompanied notes from an opera. Vibrato rate was statistically identical between the two genres at ~6.4 Hz; however, lieder featured a longer delay in vibrato onset. Vibrato extent was smaller for lieder (~112 cents) compared with opera (~138 cents). The singer's formant, which is generally associated with opera, was at times observed in the lieder recordings; however, this was at an overall significantly weaker intensity than in the opera recordings. The results were replicated in study 3, where recordings using only singers who performed in both lied and opera were analyzed. This direct comparison used 45 lieder notes and 55 opera notes and also investigated three different methods of analyzing the singer's formant. A number of consistencies and inconsistencies were identified between acoustic parameters reported in studies 2 and 3, and the beliefs of singing teachers and scholars in the literature and study 1.

The effects of emotional expression on vibrato

OBJECTIVES/HYPOTHESIS

The purpose of this study was to investigate the effect of emotional expression on several acoustic measures of vibrato, including its rate, extent, and steadiness. We hypothesized that singing a passage with emotional content would influence these variables.

STUDY DESIGN

This study used a within-subjects, repeated-measures design. Singer performance under different conditions was analyzed.

METHODS

Ten graduate student singers (eight women, two men) completed a series of tasks including sustained sung vowels at several pitch and loudness levels, an assigned song that was judged to have relatively neutral emotion, and a personal selection that included passages of intense emotion. Vowel tokens were extracted from the recordings and averaged for each task. Dependent measures included the mean fundamental frequency (F0), mean intensity, frequency modulation (FM) rate, FM extent, and measures of FM rate and extent variability.

RESULTS

The FM rate and extent were higher and the modulation variability was lower for the more emotional song than for the sustained vowels. Mean F0 and intensity were higher for the emotional song than for the neutral song.

CONCLUSIONS

Singing an emotional passage influences acoustic features of vibrato when compared with isolated, sustained vowels. The wider dynamic and pitch ranges for emotional passages only partly explain vibrato differences between emotional and neutral singing.

Common cues to emotion in the dynamic facial expressions of speech and song

Speech and song are universal forms of vocalization that may share aspects of emotional expression. Research has focused on parallels in acoustic features, overlooking facial cues to emotion. In three experiments, we compared moving facial expressions in speech and song. In Experiment 1, vocalists spoke and sang statements each with five emotions. Vocalists exhibited emotion-dependent movements of the eyebrows and lip corners that transcended speech–song differences. Vocalists’ jaw movements were coupled to their acoustic intensity, exhibiting differences across emotion and speech–song. Vocalists’ emotional movements extended beyond vocal sound to include large sustained expressions, suggesting a communicative function. In Experiment 2, viewers judged silent videos of vocalists’ facial expressions prior to, during, and following vocalization. Emotional intentions were identified accurately for movements during and after vocalization, suggesting that these movements support the acoustic message. Experiment 3 compared emotional identification in voice-only, face-only, and face-and-voice recordings. Emotion judgements for voice-only singing were poorly identified, yet were accurate for all other conditions, confirming that facial expressions conveyed emotion more accurately than the voice in song, yet were equivalent in speech. Collectively, these findings highlight broad commonalities in the facial cues to emotion in speech and song, yet highlight differences in perception and acoustic-motor production.

Intelligibility of sung vowels: the effect of consonantal context and the onset of voicing

BACKGROUND

Studies addressing the identification of sung vowels concern mainly the effect of the fundamental frequency (f0) and conclude that correct vowel identification decreases with increasing pitch. In one experiment, the impact of consonantal environment on the intelligibility of the vowels in high-pitched singing was also studied. The results of that experiment showed positive effect of the consonantal environment. This finding is in line with results that had been reported for speech in an earlier study. However, the data on singing are not as transparent as the authors suggest, and there are some conditions in the experiment that could also be controlled for more strictly. Therefore, the effect of the dynamic acoustic information encoded in the formant transitions at high fundamental frequencies is still an open question.

OBJECTIVES

The aim of the present study was to redesign and extend the above-mentioned experiment to test whether the phonetic context and the onset of the vowel uttered in isolation (namely the onset of voicing) have a positive effect on vowel identification.

METHODS

For this purpose, a vowel identification test was carried out. The stimuli included three Hungarian vowels /aː iː uː/ in three conditions (in /bVb/ context, in isolation and with eliminated onset) at seven different fundamental frequencies from 175 to 988 Hz (F3, B3, F4, B4, F5, B5, and speech). The stimuli were produced by one professional soprano singer.

RESULTS

The results show that consonantal context does not specify vowel identity in singing as clearly as it has been demonstrated for spoken utterances. In addition, no effect of vowel onset (ie, the onset of voicing) was found. Recognition percentages seemed only to be dependent on f0 and vowel quality.

CONCLUSIONS

The unexpected results lend themselves to two possible explanations: the reduction of the consonants and the undersampling of the formant transitions.

The effect of singing training on voice quality for people with quadriplegia

OBJECTIVES

Despite anecdotal reports of voice impairment in quadriplegia, the exact nature of these impairments is not well described in the literature. This article details objective and subjective voice assessments for people with quadriplegia at baseline and after a respiratory-targeted singing intervention.

STUDY DESIGN

Randomized controlled trial.

METHODS

Twenty-four participants with quadriplegia were randomly assigned to a 12-week program of either a singing intervention or active music therapy control. Recordings of singing and speech were made at baseline, 6 weeks, 12 weeks, and 6 months postintervention. These deidentified recordings were used to measure sound pressure levels and assess voice quality using the Multidimensional Voice Profile and the Perceptual Voice Profile.

RESULTS

Baseline voice quality data indicated deviation from normality in the areas of breathiness, strain, and roughness. A greater percentage of intervention participants moved toward more normal voice quality in terms of jitter, shimmer, and noise-to-harmonic ratio; however, the improvements failed to achieve statistical significance.

CONCLUSIONS

Subjective and objective assessments of voice quality indicate that quadriplegia may have a detrimental effect on voice quality; in particular, causing a perception of roughness and breathiness in the voice. The results of this study suggest that singing training may have a role in ameliorating these voice impairments.