The human voice is not only the key to human communication but also serves as the primary musical instrument. Many professions rely on the voice, but the most noticeable and visible are singers. Care of the performing voice requires a thorough understanding of the interaction between the anatomy and physiology of voice production, along with an awareness of the interrelationships between vocalisation, acoustic science and non-vocal components of performance. This review gives an overview of the care and prevention of professional voice disorders by describing the unique and integrated anatomy and physiology of singing, the roles of development and training, and the importance of the voice care team.
from the Journal of Laryngology and Otology
Vocal singing (singing with lyrics) shares features common to music and language but it is not clear to what extent they use the same brain systems, particularly at the higher cortical level, and how this varies with expertise. Twenty-six participants of varying singing ability performed two functional imaging tasks. The first examined covert generative language using orthographic lexical retrieval while the second required covert vocal singing of a well-known song. The neural networks subserving covert vocal singing and language were found to be proximally located, and their extent of cortical overlap varied with singing expertise. Nonexpert singers showed greater engagement of their language network during vocal singing, likely accounting for their less tuneful performance. In contrast, expert singers showed a more unilateral pattern of activation associated with reduced engagement of the right frontal lobe. The findings indicate that singing expertise promotes independence from the language network with decoupling producing more tuneful performance. This means that the age-old singing practice of ‘finding your singing voice’ may be neurologically mediated by changing how strongly singing is coupled to the language system. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.
from Human Brain Mapping
Long-Term Horizontal Vocal Directivity of Opera Singers: Effects of Singing Projection and Acoustic Environment
Vocal directivity refers to how directional the sound is that comes from a singer’s mouth, that is, whether the sound is focused into a narrow stream of sound projecting in front of the singers or whether it is spread out all around the singer. This study investigates the long-term vocal directivity and acoustic power of professional opera singers and how these vary among subjects, among singing projections, and among vastly different acoustic environments. The vocal sound of eight professional opera singers (six females and two males) was measured in anechoic and reverberant rooms and in a recital hall. Subjects sang in four different ways: (1) paying great attention to intonation; (2) singing as in performance, with all the emotional connection intended by the composer; (3) imagining a large auditorium; and (4) imagining a small theatre. The same song was sung by all singers in all conditions. A head and torso simulator (HATS), radiating sound from its mouth, was used for comparison in all situations. Results show that individual singers have quite consistent long-term average directivity, even across conditions. Directivity varies substantially among singers. Singers are more directional than the standard HATS (which is a physical model of a talking person). The singer’s formant region of the spectrum exhibits greater directivity than the lower-frequency range, and results indicate that singers control directivity (at least, incidentally) for different singing conditions as they adjust the spectral emphasis of their voices through their formants.
from the Journal of Voice
Listener Perception of the Effect of Abdominal Kinematic Directives on Respiratory Behavior in Female Classical Singing
Breath management training in classical singing is becoming increasingly physiologically focused, despite evidence that directives focusing on chest-wall kinematic (ribcage and abdominal) behavior effect minimal change in acoustical measures of singing. A direct and proportionate relationship between breathing behavior and vocal quality is important in singing training because singing teachers rely primarily on changes in sound quality to assess the efficacy of breath management modification. Pedagogical opinion is also strongly divided over whether the strategy of retarding the reduction in abdominal dimension during singing has a negative effect on vocal quality. This study investigated whether changes in abdominal kinematic strategy were perceptible and whether listeners preferred a particular strategy. Fourteen experienced singing teachers and vocal coaches assessed audio samples of five female classical singers whose respiratory kinematic patterns during singing had been recorded habitually and under two simple, dichotomous directives: Gradually drawing the abdomen inward and gradually expanding the abdomen, during each phrase. Listeners rated the singers on standard of singing and of breath management. Ratings analysis took into consideration changes in kinematic behavior under each directive determined from the respiratory recordings. Listener ratings for two singers were unaffected by directive. For three singers, ratings were lower when the directive opposed habitual kinematic behavior. The results did not support the pedagogical assumption of a direct and proportional link between respiratory behavior and standard of singing or that the abdomen-outward strategy was deleterious to vocal quality. The findings demonstrate the importance of considering habitual breathing behavior in both research and pedagogical contexts.
from the Journal of Voice
Patients presenting to two tertiary care voice clinics prospectively completed the SVHI. Principal component analysis was performed. Individual item to total correlations were calculated, and individual items were also evaluated for bipolar response patterns. A clinical consensus conference prioritized each individual item. Items were then eliminated, and the internal consistency was evaluated. A second cohort of patients with singing voice problems completed the Voice Handicap Index-10 (VHI-10) and SVHI-10 at two time points. Singers without voice problems also completed the SVHI-10. SVHI-10 scores were compared between the groups, correlations between the SVHI-10 and VHI-10 were performed, and test-retest reliability of the SVHI-10 assessed.
Singers with voice problems had worse SVHI-10 scores than normal singers (P < .0001, t test). Test-retest reliability was high (Spearman correlation = 0.86, P < .001). Internal consistency of the SVHI-10 demonstrated a Cronbach of .94, and the correlation between the SVHI-10 and VHI-10 was 0.7 (P < .001, Spearman correlation).
The SVHI-10 is a valuable instrument to assess self-perceived handicap associated with singing voice problems with reduced patient burden. Laryngoscope, 2009
from The Laryngoscope
Vocal tract and register changes analysed by real-time MRI in male professional singers—a pilot study
Changes of vocal tract shape accompanying changes of vocal register and pitch in singing have remained an unclear field. Dynamic real-time magnetic resonance imaging (MRI) was applied to two professional classical singers (a tenor and a baritone) in this pilot study. The singers sang ascending scales from B3 to G#4 on the vowel /a/, keeping the modal register throughout or shifting to falsetto register for the highest pitches. The results show that these singers made few and minor modifications of vocal tract shape when they changed from modal to falsetto and some clear modifications when they kept the register. In this case the baritone increased his tongue dorsum height, widened his jaw opening, and decreased his jaw protrusion, while the tenor merely lifted his uvula. The method used seems promising and should be applied to a greater number of singer subjects in the future.
The perception of modal and falsetto registers was analyzed in a material consisting of a total of 104 vowel sounds sung by 13 choir singers, 52 sung in modal register, and 52 in falsetto register. These vowel sounds were classified by 16 expert listeners in a forced choice test and the number of votes for modal was compared to the voice source parameters: (1) closed quotient (Qclosed), (2) level difference between the two lowest source spectrum partials (H1−H2), (3) AC amplitude, (4) maximum flow declination rate (MFDR), and (5) normalized amplitude quotient (NAQ, AC amplitude/MFDR* fundamental frequency). Tones with a high value of Qclosed and low values of H1−H2 and of NAQ were typically associated with high number of votes for modal register, and vice versa, Qclosed showing the strongest correlation. Some singer subjects produced tones that could not be classified as either falsetto or modal register, suggesting that classification of registers is not always feasible. ©2008 Acoustical Society of America
A research group from Tel Aviv University has successfully managed to train a computer to rate vibrato quality, and has created an application based on biofeedback to help singers improve their technique.
This pilot study aimed to investigate the effects of vocal exercises and singing on intelligibility and speech naturalness for subjects with acquired dysarthria following traumatic brain injury or stroke. A multiple case study design was used, involving pre, mid, and post-treatment assessments of intelligibility, rate, naturalness, and pause time for four subjects with dysarthria. Each subject participated in 24 individual music therapy sessions over eight weeks involving oral motor respiratory exercises, rhythmic and melodic articulation exercises, rhythmic speech cuing, vocal intonation therapy, and therapeutic singing using familiar songs. Results were measured using a standardized dysarthric speech assessment – the Sentence Intelligibility Test, waveform analysis, and ratings of speech naturalness. Statistically significant improvements in functional speech intelligibility were achieved but improvements in rate of speech were not significant. Speech naturalness improved post-treatment and a reduction in the number and length of pauses was verified via waveform analysis. Preliminary findings suggest that a program of vocal exercises and singing may facilitate more normative speech production for people with acquired dysarthria and support the need for further research in this area.
from the Journal of Voice
Previous studies suggest that singers modify articulation to avoid that the pitch frequency F0 exceeds the normal value of the first formant F1Normal. Using magnetic resonance imaging at a rate of 5 frames/s, articulation was analyzed in a professional soprano singing an ascending triad pattern from C4 to G5 (262–784Hz) on the vowels /i, e, u, o, a/. Lip and jaw opening and tongue dorsum height were measured and analyzed as function of pitch. Four or five semitones below the pitch where F0=F1Normal the tongue dorsum height was reduced in /i, e, u, a/, whereas in /o/ the lip opening was widened and in /a/ also the jaw opening was widened. At higher pitches, the jaw opening was widened in all vowels. These articulatory maneuvers are likely to raise F1 in these vowels.
from the Journal of Voice
Previous research has used perturbation analysis methods to study the singing voice. Using perturbation and nonlinear dynamic analysis (NDA) methods in conjunction may provide more accurate information on the singing voice and may distinguish vocal usage in different styles. Acoustic samples from different styles of singing were compared using nonlinear dynamic and perturbation measures. Twenty-six songs from different musical styles were obtained from an online music database (Rhapsody, RealNetworks, Inc., Seattle, WA). One-second samples were selected from each song for analysis. Perturbation analyses of jitter, shimmer, and signal-to-noise ratio and NDA of correlation dimension (D2) were performed on samples from each singing style. Percent jitter and shimmer median values were low normal for country (0.32% and 3.82%), musical theater (MT) (0.280% and 2.80%), jazz (0.440% and 2.34%), and soul (0.430% and 6.42%). The popular style had slightly higher median jitter and shimmer values (1.13% and 6.78%) than other singing styles, although this was not statistically significant. The opera singing style had median jitter of 0.520%, and yielded significantly high shimmer (P=0.001) of 7.72%. All six singing styles were measured reliably using NDA, indicating that operatic singing is notably more chaotic than other singing styles. Median correlation dimension values were low to normal, compared to healthy voices, in country (median D2=2.14), jazz (median D2=2.24), pop (median D2=2.60), MT (median D2=2.73), and soul (mean D2=3.26). Correlation dimension was significantly higher in opera (P<0.001) with median D2=6.19. In this study, acoustic analysis in opera singing gave significantly high values for shimmer and D2, suggesting that it is more irregular than other singing styles; a previously unknown quality of opera singing. Perturbation analysis also suggested significant differences in vocal output in different singing styles. This preliminary study using acoustic analysis with nonlinear dynamic measures and perturbation measures may represent a valuable procedure in quantitatively describing the properties of the singing voice. Further research with human test subjects may allow us to characterize singing styles and diagnose vocal dysfunction in the singing voice.
Predicted Singers’ Vocal Fold Lengths and Voice Classification-A Study of X-Ray Morphological Measures
from the Journal of Voice
Students admitted to the solo singing education at the University of Music Dresden, Germany have been submitted to a detailed physical examination of a variety of factors with relevance to voice function since 1959. In the years 1959-1991, this scheme of examinations included X-ray profiles of the singers’ vocal tracts. This material of 132 X-rays of voice professionals was used to investigate different laryngeal morphological measures and their relation to vocal fold length. Further, the study aimed to investigate if there are consistent anatomical differences between singers of different voice classifications. The study design used was a retrospective analysis. Vocal fold length could be measured in 29 of these singer subjects directly. These data showed a strong correlation with the anterior-posterior diameter of the subglottis and the trachea as well as with the distance from the anterior contour of the thyroid cartilage to the anterior contour of the spine. These relations were used in an attempt to predict the 132 singers’ vocal fold lengths. The results revealed a clear covariation between predicted vocal fold length and voice classification. Anterior-posterior subglottic-tracheal diameter yielded mean vocal fold lengths of 14.9, 16.0, 16.6, 18.4, 19.5, and 20.9mm for sopranos, mezzo-sopranos, altos, tenors, baritones, and basses, respectively. The data support the assumption that there are consistent anatomical laryngeal differences between singers of different voice classifications, which are of relevance to pitch range and timbre of the voice.
from the Journal of Voice
The purpose of this exploratory study was to examine the relationship between undergraduate vocal music majors’ diction acquisition abilities for singing in a nonnative language (as rated both by themselves and by their studio voice teachers) and their scores on an objective test of phonemic and stress perception. Ten students with varying levels of university voice training served as participants. The results showed significant negative correlations between each of the teachers’ four ratings and the students’ scores on the phonemic awareness subtest. In addition, 20% of the students demonstrated evidence of underdeveloped phonemic awareness skills, as indicated by their below average test performance. Considerable individual differences were also observed in the students’ abilities to track phonemes within a sequence of phonemes, count and track syllables within a sequence of syllables, and track combinations of phoneme and syllable changes in sequence, as evidenced by subtest performance scores. These findings corroborate existing reports which indicate that approximately 30% of the population does not fully develop phonemic awareness skills in the absence of special training. The findings support the utility of this objective test of phonemic and stress perception as a means of identifying students who will have difficulty with diction acquisition, and point to possibilities for pretraining to improve their response to diction instruction.
Even as American Idol reminds us of the best (and worst) that singing has to offer, a new study cautions that amateur singers and singing instructors are less sensitive than their professional peers to the subtle changes to their voices that could have a serious negative impact on their vocal health.
Effects of Increasing Time Delays on Pitch-Matching Accuracy in Trained Singers and Untrained Individuals
from the Journal of Voice
Trained singers (TS) generally demonstrate accurate pitch matching, but this ability varies within the general population. Pitch-matching accuracy, given increasing silence intervals of 5, 15, and 25 seconds between target tones and vocal matches, was investigated in TS and untrained individuals. A relationship between pitch discrimination and pitch matching was also examined. Thirty-two females (20-30 years) were grouped based on individual vocal training and performance in an immediate pitch-matching task. Participants matched target pitches following time delays, and completed a pitch discrimination task, which required the classification of two tones as same or different. TS and untrained accurate participants performed comparably on all pitch-matching tasks, while untrained inaccurate participants performed significantly less accurately than the other two groups. Performances declined across groups as intervals of silence increased, suggesting degradation of pitch matching as pitch memory was taxed. A significant relationship between pitch discrimination and pitch matching was revealed across participants.