What is “Twang”?

A single female professional vocal artist and pedagogue sang examples of “twang” and neutral voice quality, which a panel of experts classified, in almost complete agreement with the singer's intentions. Subglottal pressure was measured as the oral pressure during the occlusion during the syllable /pae/. This pressure tended to be higher in “twang,” whereas the sound pressure level (SPL) was invariably higher. Voice source properties and formant frequencies were analyzed by inverse filtering. In “twang,” as compared with neutral, the closed quotient was greater, the pulse amplitude and the fundamental were weaker, and the normalized amplitude tended to be lower, whereas formants 1 and 2 were higher and 3 and 5 were lower. The formant differences, which appeared to be the main cause of the SPL differences, were more important than the source differences for the perception of “twanginess.” As resonatory effects occur independently of the voice source, the formant frequencies in “twang” may reflect a vocal strategy that is advantageous from the point of view of vocal hygiene.     

Preliminary study of two methods of treatment for laryngeal nodules

To date, a limited number of formal studies have assessed the efficacy of voice therapy for laryngeal nodules. The present study represents a preliminary stage of inquiry in a series of planned studies on this topic. Thirteen women with nodules participated as paid subjects. Some subjects received “confidential voice therapy,” some received “resonant voice therapy,” and some received no therapy (control condition) over a period of 2 weeks. Pre- and post-therapy measures of phonatory effort, auditory-perceptual status of voice, and laryngeal appearance provided evidence of a benefit from therapy. Baseline measures were then repeated 2 weeks after therapy was terminated. The final results indicated that, for auditory-perceptual and phonatory effort measures, the likelihood of benefiting from therapy directly covaried with compliance scores (reflecting the reported extraclinical utilization of the therapy technique), but not with therapy type (confidential vs. resonant voice therapy). At this level, the results point to the importance of assessing not only therapy type but also compliance in future, larger studies. A series of other positive and negative factors in the present research design were identified based on the results. These should be considered in future studies.     

G. Paul Moore lecture: Rational thought: The impact of voice science upon voice care

Recent evolution in scientific knowledge and technology has led to monumental improvement in the standard of care for patients with voice disorders. New concepts in anatomy, physiology, measurement, and analysis have provided voice care professionals with not merely better understanding, but moreover an extensive vocabulary with which to think about voice function and dysfunction. Previously, we had to depend too much upon anecdote and “the art of medicine.” Thanks to scientific advances, we now have the tools we need for rational thought about the human voice. This is the fundamental change responsible for recent great advances in voice care.     

Perceptual evaluations of voice scatter in unison choir sounds

The preferences of experienced listeners for pitch and formant frequency dispersion in unison choir sounds were explored using synthesized stimuli. Two types of dispersion were investigated: (a) pitch scatter, which arises when voices in an ensemble exhibit small differences in mean fundamental frequency, and (b) spectral smear, defined as such dispersion of formants 3 to 5 as arises from differences in vocal tract length. Each stimulus represented a choir section of five bass, tenor, alto, or soprano voices, producing the vowel [u], [a], or [w]. Subjects chose one dispersion level out of six available, selecting the “maximum tolerable” in a first run and the “preferred” in a second run. The listeners were very different in their tolerance for dispersion. Typical scatter choices were 14 cent standard deviation for “tolerable” and 0 or 5 cent for “preferred.” The smear choices were less consistent; the standard deviations were 12 and 7%, respectively. In all modes of assessment, the largest dispersion was chosen for the vowel [u] on a bass tone. There was a vowel effect on the smear choices. The effects of voice category were not significant.     

Voice and Physical Appearance in Female-to-Male Transsexuals

The study aims to investigate if a similar interaction between physical appearance and voice could be found in female-to-male transsexuals as had been observed in male-to-female transsexuals. A panel of judges rated “maleness” of seven female-to-male transsexuals from video-recorded speech samples using three modes of presentation: auditory-only presentation, visual-only presentation, and audiovisual presentation. For the group of transsexuals as a whole, no significant differences were found between scores given in the auditory-only mode or the visual-only mode and those given in the audiovisual mode. Analysis of individual results, however, yielded significant differences in some individuals and there was some relation with hormone treatment. There was no significant correlation between the ratings of “maleness” in the auditory-only mode and fundamental frequency. Physical appearance in female-to-male transsexuals appears not to be a strong influencing factor in general, but may interact with gender recognition based on the voice in some individuals. The absence of a correlation between fundamental frequency and rating of maleness could mean that in female-to-male transsexuals, fundamental frequency is a relatively less important factor for gender expression or perhaps also that a higher voice in males is more accepted than a lower voice in females.     

“Alternative medical therapy” use among singers: Prevalence and implications for the medical care of the singer

Singers are extremely conscious of health problems that affect their voices and well-being and often take an active role in seeking care for these problems. They frequently seek treatment from providers or with modalities considered “alternative” to traditional medical care. A survey of singers was completed to elucidate their attitudes and practices regarding “alternative modalities” of medical care. Frequently singers will self-medicate or take advice from people not well versed in the special needs of a professional voice user. They will fail to share this information with the physician when seeking “traditional” medical care. These practices may predispose the singer to suboptimal or even dangerous care. These results are discussed, as well as the implications for the medical physician treating the singer. The possible detrimental pharmacologic effects of “natural therapies” widely used by singers are presented, with special attention to the particular concerns for the professional singer     

Phonetographic profiles and F0-SPL characteristics of untrained versus trained vocal groups

The phonetogram has been recommended as an international tool for voice analysis. However, the capability of this technique to distinguish between different vocal groups has not been clearly established. The purpose of this study was to examine untrained versus trained vocalists using the phonetogram and the fundamental frequency by intensity (F₀/SPL) information derived through that method. In this study, “musical” or “controlled” ranges of phonation were stressed rather than “physiological” ranges. Results indicated that (a) characteristic phonetographic profiles may be established for untrained versus trained vocalists, and (b) trained vocalists show significantly increased capability in terms of F₀ range and maximum, minimum, and comfortable SPL production. Elicitation of “controlled” phonations may be the key to revealing the underlying vocal capabilities of seemingly different vocal groups.     

Preliminary evaluation of selected acoustic and glottographic measures for clinical phonatory function analysis

Acoustic and glottographic measures may provide important information that could enhance clinical management and documentation of vocal dysfunction. Acoustic measures such as jitter and shimmer reflect “short-term” perturbations, or instabilities of the voice, and the coefficients of variation for frequency and for amplitude reflect “long-term” perturbations. Interpretations of these acoustic measures are based on the assumption that vocal perturbations may be related to laryngeal tissue abnormalities, asymmetries in vocal fold movement, or neuromuscular fluctuations in the respiratory, laryngeal, or vocal tract systems. The abduction quotient is a glottographic measure related to laryngeal adduction and is obtained from an analysis of the electroglottograph signal. The adduction measure appears to be independent of the acoustic perturbation measures. Interpretations of the acoustic and adductory measures may, therefore, complement each other for greater understanding of a patient's laryngeal behavior. Visual displays of the acoustic and glottographic signals also are discussed to demonstrate their value in voice signal interpretations. Case studies illustrate potential interpretations of the acoustic perturbation and abduction quotient measures.     

Comparison of microphone and neck-mounted accelerometer monitoring of the performing voice

One method for monitoring individuals in live performances may be the use of vibration sensors, or accelerometers, rather than using microphones that pick up environmental noises as well as the vocal signals of interest. This study was concerned with a comparison of microphone and accelerometer monitoring of the amplitude characteristics of singers' voices. From the results obtained it appears that accelerometers are not applicable for monitoring amplitude characteristics of the voice, but are useful for periodicity measures. In addition, accelerometers may be of use in verifying the kinesthetic patterns sensed by a performer during the process of “singing into a mask” or producing the singer's “ring.”     

Supraglottic contribution to voice quality

Although there has been continuing interest in voice quality, much of this research has focused on the vocal folds rather than the supraglottal structures. This paper reports the use of videoendoscopy for studying supraglottal participation in various singing tasks. In a preliminary study presented last year by the present authors, CT scanning was used to corroborate videoendoscopic observation. Vocal tract activities observed included variation of laryngeal height with pitch, variation of pharyngeal wall dimension with pitch and vowel, and marked supraglottic constriction with certain vocal imitations. In order to gain a better understanding of vocal training, and its effect upon vocal tract physiology, a study was designed using videoendoscopy to observe singers with significant experience and training while performing various vocal tasks. The tasks focused on the following: (1) vocal tract activity associated with pitch changes; (2) the physiology involved in the production of “cover”; (3) the structures involved in the production of vibrato; and (4) the physiology of the singer's “ring.” It would appear that videoendoscopy will become increasingly more valuable to the voice community as our understanding of vocal tract physiology improves.     

Singing power ratio: Quantitative evaluation of singing voice quality

This paper presents a parameter for objectively evaluating singing voice quality. Power spectrum of vowel sound / a / was analyzed by Fast Fourier Transform. The greatest harmonics peak between 2 and 4 kHz and the greatest harmonics peak between 0 and 2 kHz were identified. Power ratio of these peaks, termed singing power ratio (SPR), was calculated in 37 singers and 20 nonsingers. SPR of sung / a / in singers was significantly greater than in nonsingers. In singers, SPR of sung / a / was significantly greater than that of spoken / a /. By digital signal processing, power spectrum of sung / a / was varied, and the processed sounds were perceptually analyzed. SPR had a significant relationship with perceptual scores of “ringing” quality. SPR provides an important quantitative measurement for evaluating singing voice quality for all voice types, including soprano.     

Physiological differences between the trained and untrained speaking and singing voice

This study concerns the premier singing voice and its relationship to physiological aptitude. Research literature is reviewed that indicates that during singing the trained singer uses different physiological strategies in comparison with the untrained singer, and that the noted physiological differences (respiratory, laryngeal, articulatory) occur during singing only and not during speech. Further, a study was conducted that compared the ability of trained singers versus untrained individuals to (a) discriminate differences in self-generated air pressures and (b) produce and maintain a constant level of air pressure. No significant differences were found between the trained and untrained groups in their ability to discriminate and/or control breath pressure. Combined results of previous studies and present findings lead to the tentative conclusion that the excelled singer is not physiologically endowed and/or “gifted,” but rather has benefited from technical voice training     

Laryngeal adduction in resonant voice

The primary question in this study was whether subjects with nodules and subjects with healthy larynges would produce “resonant voice” with a similar laryngeal configuration. A second question regarded whether the electroglottographic closed quotient (EGG CQ) could be used to noninvasively distinguish resonant from other voice types. Twelve adult singers and actors served as subjects, including 6 persons with healthy larynges and 6 persons with nodules. Performers were used as an attempt to maximize token validity and stability. Subjects produced repeated tokens of resonant, pressed, normal, and breathy voice during sustained vowels. Laryngeal adduction was directly estimated using blinded, ordinal, visual-perceptual ratings based on videoscopic views of the larynx. EGG CQs were further calculated based on separate trials. The perceptual ratings indicated that subjects in both groups produced resonant voice with a barely adducted or barely abducted laryngeal configuration that was distinct from configurations for pressed and breathy (but not normal) voice. Previous literature suggests that this configuration may be relevant in many cases of voice therapy (I). Average CQs distinguished resonant from pressed voice, but inconsistently distinguished resonant from breathy voice. Further CQs were reliably different across healthy subjects and subjects with nodules. Thus, the utility of this measure to noninvasively estimate resonant voice may be limited, particularly without ongoing subject-specific calibration procedures.     

A critical view of the yawn-sigh as a voice therapy technique

The purpose of this study was to take a critical look at a voice therapy technique known as the yawn-sigh. The voiced sigh as an approach in voice therapy has had increased use in recent years, particularly with problems of vocal hyperfunction. In this study, the physiology of the yawn-sigh was studied with video nasoendoscopy in eight normal subjects; their taped voices were also studied acoustically for possible fundamental frequency and formant changes in producing selected vowels under normal and sigh conditions. Although each subject was given a model by the examiner of a yawn-sigh, one of the eight subjects could not produce a true yawn-sigh. Endoscopic findings for seven of the eight subjects performing the yawn-sigh demonstrated retracted elevation of the tongue, a lower positioning of the larynx, and a widened pharynx. Acoustic analyses for the seven subjects producing the sigh found a marked lowering of the second and third formants. Implications for using the yawn-sigh in voice therapy are given, such as using a modified “silent” yawn-sigh, as an easy method for producing greater vocal tract relaxation.     

Voice Source Characteristics in Mongolian “Throat Singing” Studied with High-Speed Imaging Technique, Acoustic Spectra, and Inverse Filtering

Mongolian “throat singing” can be performed in different modes. In Mongolia, the bass-type is called Kargyraa. The voice source in bass-type throat singing was studied in one male singer. The subject alternated between modal voice and the throat singing mode. Vocal fold vibrations were observed with high-speed photography, using a computerized recording system. The spectral characteristics of the sound signal were analyzed. Kymographic image data were compared to the sound signal and flow inverse filtering data from the same singer were obtained on a separate occasion. It was found that the vocal folds vibrated at the same frequency throughout both modes of singing. During throat singing the ventricular folds vibrated with complete but short closures at half the frequency of the true vocal folds, covering every second vocal fold closure. Kymographic data confirmed the findings. The spectrum contained added subharmonics compared to modal voice. In the inverse filtered signal the amplitude of every second airflow pulse was considerably lowered. The ventricular folds appeared to modulate the sound by reducing the glottal flow of every other vocal fold vibratory cycle.     

Comfortable effort level revisited

The purpose of this study was to measure the variability of frequency and intensity of speech, using multiple voice samples obtained over a period of time at a speaker's “comfortable effort level.” Variability in vocal output within and across several experimental sessions was assessed from measures of speaking fundamental frequency (SFF) and vocal intensity for utterances repeated three times a day over a 3-day period. Three distinct age groups of men and women—young, middle-aged and elderly—repeated the vowel /a/, read a standard passage, and spoke extemporaneously during each experimental session. Results indicated that variability in SFF and intensity were present across experimental sessions, age groups, gender, and speaking samples. Generally, group means indicated that ±1 semitone of variability for SFF and 2 db sound pressure level (SPL) variation in vocal intensity from any one experimental session to the next could be expected; individual variations within any group may reach two semitones and 6 db SPL.     

Acoustic concomitants of emotional expression in operatic singing: The case of lucia in Ardi gli incensi

Two excerpts from the cadenza in Ardi gli incensi from Donizetti's opera Lucia di Lammermoor were acoustically analyzed for five recorded versions of the cadenza by Toti dal Monte, Maria Callas, Renata Scotto, Joan Sutherland, and Edita Gruberova. These acoustic parameters of the singing voices were correlated with preference and emotional expression judgments, based on pairwise comparisons, made by a group of experienced listener-judges. In addition to showing major differences in the voice quality of the five “dive” studied, the acoustic parameters suggested which vocal cues affect listener judgments. Two component scores, based on a factorial-dimensional analysis of the acoustic parameters, predicted 84% of the variance in the preference ratings.     

Performance demands and the performer's vocal capabilities

Performers could benefit by knowing in advance and by objective means, what vocal requirements for a particular role or performance are potentially harmful to them. By combining the concept of the “phonetogram” (F₀ — SPL Profile) with automatic pitch extraction of vocal performances, a contour of the vocal performance demands can be superimposed on the profile of the individual's vocal capabilities. Vocal productions that are near to or exceeding the vocal capabilities of a performer can be presumed to be potentially hazardous. Likewise, performance demands that are clearly within the profile of a given individual can be presumed to be nonhazardous with respect to pitch and amplitude range.