Change in messa di voce characteristics during 3 years of classical singing training at the tertiary level.

A 3-year longitudinal study was conducted to investigate changes in vocal quality as a result of singing training at a tertiary level conservatorium in Australia. Singers performed a messa di voce (MDV) at intervals of 6 months over the 3-year period of training. The study investigated the evolving acoustic features of the singers' voices exhibited during the MDV, including sound pressure level (SPL), short-term energy ratio (STER), duration, and vibrato parameters of the fundamental frequency (F0), SPL, and STER. The maximum SPL exhibited a marginal systematic increase over the training period, but the maximum STER did not systematically change. F0 vibrato extent increased significantly, whereas the extent of SPL and STER vibrato did not change significantly.

Change in vibrato rate and extent during tertiary training in classical singing students.

OBJECTIVES: Vibrato is an integral and desirable feature of the classical singing voice. For elite singing students, achieving and developing vibrato may constitute one of the essential elements of their vocal training, although it is not necessarily a focus of that training. STUDY DESIGN: In this longitudinal study, we measured vibrato rate (VR) and vibrato extent (VE) and regularity (SD) of VR and VE in student singers over the course of four semesters of tertiary level voice training at a conservatorium of music to determine how these parameters changed during training. METHOD: Fifteen singers completed four semesters (2 years) of training. Singers performed four sustained pitches across their vocal range. Peaks and troughs of vibrato were isolated from the fundamental frequency trace to calculate VR in hertz and VE in semitones. RESULTS: Analysis using linear mixed models revealed significant increases in VE and decreases in VRSD over time. VR was within expected limits for classical singers in all semesters, and small VR reductions were not statistically significant between semesters over 2 years of training. VE showed significant increases between the start of year 1 and year 2. Periodicity of singers' VR (SD) improved over training, with significant decreases to VRSD over time. There was no significant change to VESD. CONCLUSIONS: Future studies will ascertain whether further changes to VR and VE occur over longer training periods, or whether the major changes occur early in tertiary training.

Acoustic and perceptual appraisal of vocal gestures in the female classical voice.

Long-term average spectra (LTAS) have identified features in the sounds of singers and have compared different vocal qualities based on energy changes that occur during different vocal tasks. In this study, we compared the perceptual ratings of vocal quality of expert pedagogues with acoustic measures performed on LTAS. Fifteen expert judges rated 24 samples with six repeats of six advanced singing students under two conditions: "optimal" (O), which represented the application of the maximal open throat technique; and "suboptimal" (SO), which represented the application of the reduced open throat technique. LTAS were performed on each singing sample, and two conventional assessments of peak energy height [singing power ratio (SPR)] and peak area [energy ratio (ER)] were calculated on each LTAS. Perceptual scores, SPR, and ER were rank ordered. We then compared perceptual rankings with rankings of acoustic measures (SPR and ER) to assess whether these acoustic measurements matched the perceptual judgments of vocal quality. Although we found the expected significant relationship between SPR and ER, there was no relationship between perceptual ratings of vocal samples or singers based on SPR or ER. These findings suggest that because LTAS measures are not consistent with perceptual ratings of vocal quality, such measurements cannot define a voice of quality. Future research with LTAS to assess vocal quality should consider alternative measures that are more sensitive to subtle differences in vocal parameters.

The effects of open throat technique on long term average spectra (LTAS) of female classical voices.

In the third of a series of studies on open throat technique, we compared long term average spectra (LTAS) of six advanced singing students under three conditions: 'optimal' (O), representing maximal open throat, 'sub-optimal' (SO), using reduced open throat, and loud sub-optimal (LSO) to control for the effect of loudness. Using a series of univariate repeated measures ANOVAs with planned orthogonal contrasts, we tested the hypotheses that sound pressure level (SPL) and the ratio of spectral energy in peaks and areas between 0-2 kHz and 2-4 kHz would be reduced in SO and LSO compared to O. There were significant differences between SO and LSO but hypotheses were not confirmed for O. These findings do not accord with differences in vibrato extent and onset between O and SO/LSO (Mitchell and Kenny, in press). These results suggest that while LTAS provides information on energy distribution, measuring spectral energy areas appears to be the most sensitive measure of energy distribution between conditions. Plotting the differences between O and SO/LSO pairs of LTAS clearly indicates the areas of spectral change. The findings from this study also indicate that LTAS are not sufficiently sensitive to measure vocal timbre as they were not consistent with perceptual or other acoustic studies of the same samples.

The impact of 'open throat' technique on vibrato rate, extent and onset in classical singing.

Mitchell, Kenny et al. (2003) identified 'open throat' as integral to the production of an even and consistent sound in classical singing. In this study, we compared vibrato rate, extent and onset of six advanced singing students under three conditions: 'optimal' (O), representing maximal open throat; 'sub-optimal' (SO), using reduced open throat; and loud sub-optimal (LSO), using reduced open throat but controlling for the effect of loudness. Fifteen expert judges correctly identified the sound produced when singers used open throat with 85% accuracy. Having verified the technique perceptually, we used a series of univariate repeated measures ANOVAs with planned orthogonal contrasts to test the hypotheses that frequency modulations associated with vibrato rate, extent and onset would vary outside acceptable or desirable parameters for SO and LSO. Hypotheses were confirmed for vibrato extent and onset but not for rate. There were no significant differences between SO and LSO on any of the vibrato parameters. As vibrato is considered a key indicator of good singing, these findings suggest that open throat is important to the production of a good sound in classical singing.

Defining 'open throat' through content analysis of experts' pedagogical practices.

'Open throat' is a term regularly used in the singing studio, but agreement across pedagogues as to its definition and function has not yet been assessed. Fifteen expert singing pedagogues participated in a qualitative study involving a semi-structured interview to explore current thinking regarding terminology, pedagogy, sound quality and the perceived physiology to achieve open throat, as used in the singing studio. Most teachers included the use of the technique as a fundamental in singing training, and were positive about the sound quality it achieved, especially in classical singing. The purpose of the technique was described as a way of maximizing pharyngeal space and/or achieving abduction of the ventricular folds.