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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. [ABSTRACT FROM AUTHOR]

The usefulness of a term depends on the extent to which it means the same thing to different people. In this investigation we examine the term 'support', commonly used in vocal pedagogy. Singing lessons given by co-author SS to five students at varying stages were recorded on DAT. By listening to these recordings, she selected 42 examples, each a few seconds long, that she found representative of different degrees of support ranging from perfect to nil. These examples were presented in random order to nine experts, all with a professional involvement in singing. Thirteen of the stimuli occurred twice in the test. Intra- and inter-rater reliability were found to be high, Cronbach alpha=0.910, and mean correlation 0.743 (SD 0.137). These data support the assumption that the term support has a similar meaning to voice experts and should thus be useful in voice terminology. [ABSTRACT FROM AUTHOR]

Background and Aim: To date, little research is available that objectively quantifies female adolescent singing-voice characteristics in light of the physiological and functional developments that occur from puberty to adulthood. This exploratory study sought to augment the pool of data available that offers objective voice analysis of female singers in late adolescence. Methods: Using long-term average spectra (LTAS) and inverse filtering techniques, dynamic range and voice-source characteristics were determined in a cohort of vocally healthy cis-gender female adolescent singers (17 to 19 years) from high-school choirs in Aotearoa New Zealand. Non-parametric statistics were used to determine associations and significant differences. Results: Wide intersubject variation was seen between dynamic range, spectral measures of harmonic organisation (formant cluster prominence, FCP), noise components in the spectrum (high-frequency energy ratio, HFER), and the normalised amplitude quotient (NAQ) suggesting great variability in ability to control phonatory mechanisms such as subglottal pressure (P sub ), glottal configuration and adduction, and vocal tract shaping. A strong association between the HFER and NAQ suggest that these non-invasive measures may offer complimentary insights into vocal function, specifically with regard to glottal adduction and turbulent noise in the voice signal. Conclusion: Knowledge of the range of variation within healthy adolescent singers is necessary for the development of effective and inclusive pedagogical practices, and for vocal-health professionals working with singers of this age. LTAS and inverse filtering are useful non-invasive tools for determining such characteristics.

Purpose: In overtone singing a singer produces two pitches simultaneously, a low-pitched, continuous drone plus a melody played on the higher, flutelike and strongly enhanced overtones of the drone. The purpose of this study was to analyse underlying acoustical, phonatory and articulatory phenomena. Methods: The voice source was analyzed by inverse filtering the sound, the articulation from a dynamic MRI video of the vocal tract profile, and the lip opening from a frontal-view video recording. Vocal tract cross-distances were measured in the MR recording and converted to area functions, the formant frequencies of which computed. Results: Inverse filtering revealed that the overtone enhancement resulted from a close clustering of formants 2 and 3. The MRI material showed that for low enhanced overtone frequencies ( F E ) the tongue tip was raised and strongly retracted, while for high F E the tongue tip was less retracted but forming a longer constriction. Thus, the tongue configuration changed from an apical/anterior to a dorsal/posterior articulation. The formant frequencies derived from the area functions matched almost perfectly those used for the inverse filtering. Further, analyses of the area functions revealed that the second formant frequency was strongly dependent on the back cavity, and the third on the front cavity, which acted like a Helmholtz resonator, tuned by the tongue tip position and lip opening. Conclusions: This type of overtone singing can be fully explained by the well-established source-filter theory of voice production, as recently found by Bergevin et al. [1] for another type of overtone singing.

Resonance tube phonation in water (RTPW) is commonly used in voice therapy, particularly in Finland and Sweden. The method is believed to induce a lowering of the vertical laryngeal position (VLP) in phonation as well as variations of the oral pressure, possibly inducing a massage effect. This pilot study presents an attempt to measure VLP and oral pressure in two subjects during RTPW and during phonation with the free tube end in air. VLP is recorded by means of a dual-channel electroglottograph. RTPW was found to lower VLP in the subjects, while it increased during phonation with the tube end in air. RTPW caused an oral pressure modulation with a bubble frequency of 14-22 Hz, depending mainly on the depth of the tube end under the water surface. The results indicate that RTPW lowers the VLP instantly and creates oral pressure variations.

The significance of nasal resonance and anti-resonance to voice production is a classical issue in vocal pedagogy and voice research. The complex structure of the nasal tract produces a complex frequency response. This complexity must be heavily influenced by the morphology of the paranasal cavities, but their contributions are far from being entirely understood. Detailed analyses of these cavities are difficult because of their limited accessibility. Here we test different methods aiming at documenting the acoustical properties of the paranasal tract. The first set of experiments was performed under in vivo conditions, where the middle meatus was occluded by means of targeted application of a maltodextrin mass under endoscopic control. The efficiency of this occlusion method was verified by measuring the nasal nitric oxide (NO) output during humming. In another experiment the frequency responses to sine sweep excitation of an epoxy mould of a nasal cavity were measured, with and without elimination of paranasal sinuses. The third experiment was conducted in a cadaveric situs, with and without maltodextrin occlusion of the middle meatus and the sphenoidal ostia. The results show that some nasal tract resonances were unaffected by the manipulation of the paranasal cavities. Providing access to a maxillary sinus resulted in marked dips in the response curve while access to the sphenoidal ostium caused only minor effects.

Long-term-average spectrum (LTAS) characteristics were analyzed for ten Kunqu Opera singers, two in each of five roles. Each singer performed singing, stage speech, and conversational speech. Differences between the roles and between their performances of these three conditions are examined. After compensating for Leq difference LTAS characteristics still differ between the roles but are similar for the three conditions, especially for Colorful face (CF) and Old man roles, and especially between reading and singing. The curves show no evidence of a singer's formant cluster peak, but the CF role demonstrates a speaker's formant peak near 3 kHz. The LTAS characteristics deviate markedly from non-singers' standard conversational speech as well as from those of Western opera singing.

Certain spectrum characteristics have been identified as important for register equalization around the male passaggio, an effect ascribed to formant tuning although descriptions of formant tuning diverge. Eight professional singers sang scales including their passaggio range on different vowels, applying two formant tuning strategies as found in (1) classical and (2) non-classical singing. Formant frequencies were measured using inverse filtering. Results revealed differences between the two strategies. For the classical formant tuning, systematic changes of formant frequencies with pitch were observed. For the highest note sung on /a/, F1 was below the second partial and F2 in the vicinity of the third. Similar spectrum characteristics were achieved by different F1 and F2 values between singers.

In this investigation the voice source from trained boy singers was processed with a transfer function that contained the singer's formant cluster of a bass, a baritone, or a tenor. The modified voices were evaluated by a panel of highly specialized experts. The experts were asked 1) to assess how similar the examples sounded to the voice of the last castrato Alessandro Moreschi, and 2) to rate how similar they thought the examples were to their imagination of an 18th-century castrato voice. For both questions, the voices with tenor formants produced significantly higher ratings than the other voice types. However, the mean ratings for the second question were generally lower than those for the first.

Phonation threshold pressure (PTP), frequently used for characterizing vocal fold properties, is often difficult to measure. This investigation analyses the lowest pressure initiating vocal fold collision (CTP). Microphone, electroglottograph (EGG), and oral pressure signals were recorded, before and after vocal warm-up, in 15 amateur singers, repeating the syllable /pa:/ at several fundamental frequencies with gradually decreasing vocal loudness. Subglottal pressure was estimated from oral pressure during the p-occlusion, using the audio and the EGG amplitudes as criteria for PTP and CTP. The coefficient of variation was mostly lower for CTP than for PTP. Both CTP and PTP tended to be higher before than after the warm-up. The results support the conclusion that CTP is a promising parameter in investigations of vocal fold characteristics.

The voice source differs between modal and falsetto registers, but singers often try to reduce the associated timbral differences, some even doubting that there are any. A total of 54 vowel sounds sung in falsetto and modal register by 13 male more or less experienced choir singers were analyzed by inverse filtering and electroglottography. Closed quotient, maximum flow declination rate, peak-to-peak airflow amplitude, normalized amplitude quotient, and level difference between the two lowest source spectrum partials were determined, and systematic differences were found in all singers, regardless of experience of singing. The observations seem compatible with previous observations of thicker vocal folds in modal register.

The subglottal pressure (Ps) and voice source characteristics of five professional baritone singers have been analyzed and the normalized amplitude quotient (NAQ), defined as the ratio between peak-to-peak pulse amplitude and the negative peak of the differentiated flow glottogram and normalized with respect to the period time, was used as an estimate of glottal adduction. The relationship between Ps and NAQ has been investigated in female subjects in two earlier studies. One of these revealed NAQ differences between both singing styles and phonation modes, and the other, based on register differences in female musical theatre singers, showed that NAQ differed between registers for the same Ps value. These studies thus suggest that NAQ and its variation with Ps represent a useful parameter in the analysis of voice source characteristics. The present study aims at increasing our knowledge of the NAQ parameter further by finding out how it varies with pitch and Ps in professional classically trained baritone singers, singing at high and low pitch (278 Hz and 139 Hz, respectively). Ten equally spaced Ps values were selected from three takes of the syllable [pae:], initiated at maximum vocal loudness and repeated with a continuously decreasing vocal loudness. The vowel sounds following the selected Ps peaks were inverse filtered. Data on peak-to-peak pulse amplitude, maximum flow declination rate and NAQ are presented.

Long-term-average spectrum (LTAS) is an efficient method for voice analysis, revealing both voice source and formant characteristics. However, the LTAS contour is non-uniformly affected by vocal loudness. This variation was analyzed in 15 male and 16 female untrained voices reading a text 7 times at different degrees of vocal loudness, mean change in overall equivalent sound level (Leq) amounting to 27.9 dB and 28.4 dB for the female and male subjects. For all frequency values up to 4 kHz, spectrum level was strongly and linearly correlated with Leq for each subject. The gain factor, that is to say, the rate of level increase, varied with frequency, from about 0.5 at low frequencies to about 1.5 in the frequency range 1.5-3 kHz. Using the gain factors for a subject, LTAS contours could be predicted at any Leq within the measured range, with an average accuracy of 2-3 dB below 4 kHz. Mean LTAS calculated for an Leq of 70 dB for each subject showed considerable individual variation for both males and females, SD of the level varying between 7 dB and 4 dB depending on frequency. On the other hand, the results also suggest that meaningful comparisons of LTAS, recorded for example before and after voice therapy, can be made, provided that the documentation includes a set of recordings at different loudness levels from one recording session.

Singers performing in popular styles of music mostly rely on feedback provided by monitor loudspeakers on the stage. The highest sound level that these loudspeakers can provide without feedback noise is often too low to be heard over the ambient sound level on the stage. Long-term-average spectra of some orchestral accompaniments typically used in pop music are compared with those of classical symphonic orchestras. In loud pop accompaniment the sound level difference between 0.5 and 2.5 kHz is similar to that of a Wagner orchestra. Long-term-average spectra of pop singers' voices showed no signs of a singer's formant but a peak near 3.5 kHz. It is suggested that pop singers' difficulties to hear their own voices may be reduced if the frequency range 3-4 kHz is boosted in the monitor sound.

Vocal registers are generally assumed to be associated with the voice source, i.e. the pulsating transglottal airflow. The waveform of this airflow was analysed by inverse filtering in professional singers, four counter tenors, five tenors, and four baritones singing the syllable [pae:] in soft, middle, and loud voice in modal and falsetto/counter tenor register. Subglottal pressure, estimated from the intra-oral pressure during the occlusion for the consonant [p], closed quotient, relative glottal leakage, and the relative level of the fundamental were analysed. The counter tenors used comparatively low subglottal pressures and mostly showed a closed phase in their flow glottogram waveform. For a given value of the closed quotient, the fundamental tended to be stronger in falsetto than in modal register. The observed voice source differences between the registers seem related to a greater vocal fold thickness in modal than in falsetto register.

The voice is apparently used in quite different manners in different styles of singing. Some of these differences concern the voice source, which varies considerably with loudness, pitch, and mode of phonation. We attempt to describe voice source differences between Classical, Pop, Jazz and Blues styles of singing as produced in a triad melody pattern by a professional female singer in soft, middle and loud phonation. An expert panel was asked to identify these triads as examples of either Classical, Pop, Jazz or Blues. The voice source was analysed by inverse filtering. Subglottal pressure Ps, closed quotient QClosed, glottal compliance (ratio between the air volume contained in a voice pulse and Ps), and the level difference between the two lowest source spectrum partials were analysed in the styles and in four modes of phonation: breathy, flow, neutral, and pressed. The same expert panel rated the degree of pressedness in the entire material. Averages across pitch were calculated for each mode and style and related to their total range of variation in the subject. The glottogram data showed a high correlation with the ratings of pressedness. Based on these correlations a pressedness factor was computed from the glottogram data. A phonation map was constructed with the axes representing mean adduction factor and mean Ps, respectively. In this map Classical was similar to flow phonation, Pop and Jazz to neutral and flow phonation, and Blues to pressed phonation.

Register transitions were identified by a group of five experts on child voices in recordings of 15 10-year-old children who sustained the vowel [a:] at different pitches throughout their vocal range. Two had mutational voices, seven had deviant voices and six were controls with normal voices. The control group had one register transition at a mean fundamental frequency of 511 Hz, or about 25% higher than in adult voices. This difference between adult and child voices may be because of the difference in trachea length, as proposed by Titze (J. Voice 1988; 3: 183-194). Children with either functional or physiological voice deviations exhibited a transition at a mean frequency of 417 Hz. A second transition was found in four voices at a mean frequency of 902 Hz. No correlation was found between the occurrence of register transitions and discontinuities in the upper and lower voice range profile contours.