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

Speech Production in Healthy Older Adults With or Without Amateur Singing Experience

PURPOSE

Amateur singing is a universal, accessible, and enjoyable musical activity that may have positive impacts on human communication. However, evidence of an impact of singing on speech articulation is still scarce, yet understanding the effects of vocal training on speech production could provide a model for treating people with speech deficits. The aim of this study was to examine speech production in younger and older adults with or without amateur singing experience.

METHOD

Thirty-eight amateur singers (aged 20-87 years, 23 women and 15 men) and 40 nonmusician active controls (aged 23-88 years, 19 women and 21 men) were recruited. A set of tasks were used to evaluate the oral motor sphere: two voice production tasks, a passage reading task, and a modified diadochokinetic (DDK) rates task performed at a natural rhythm and as quickly as possible.

RESULTS

Our results show that older age was associated with lower reading rate, lower articulation rate, and articulation rate variability in the DDK task, as well as reduced accuracy for the phonologically complex stimuli. Most importantly, our results show an advantage for singers over cognitively active nonsingers in terms of articulatory accuracy in the most challenging situations.

CONCLUSION

This result suggests extended maximal performance capacities in amateur singers perhaps resulting from the articulatory efforts required during singing.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24274813.

The intensities of vowels and plosive bursts and their impact on text intelligibility in singinga)

In classical singing, there are often problems with the intelligibility of sung text. The present study aims to test the hypotheses that (1) in loud operatic singing, compared with speaking, the intensity of voiceless plosives increases less than the intensity of vowels, leading to poorer recognition of plosives; and (2) pronouncing the plosive bursts with greater intensity improves their recognition. The acoustic analysis of nine opera arias in Italian from the Classical and Romantic periods performed by ten classically trained singers showed that the average difference in the intensity of vowels when sung and spoken was 14.6 dB [standard deviation (SD) = 7.2 dB], while the difference in the intensity of voiceless plosive bursts was only 6.6 dB (SD = 6 dB). In a perception test with 73 participants, increasing the intensity of the plosive bursts generally improved the recognition of plosives in the sung /a-plosive-a/ sequences, but mainly when reverberation and/or pink noise imitating instrumental accompaniments were added to the stimuli. At the same time, recognition of plosives was often better than chance even when the plosive burst was missing and replaced by silence.

An Acoustic Examination of Pitch Variation in Soprano Singing

INTRODUCTION

The ability to perform acoustic inspection of data and to correlate the results with perceptual and physiological aspects facilitates vocal behavior analysis. The singing voice has specific characteristics and parameters that are involved during the phonation mechanism, which may be analyzed acoustically.

OBJECTIVE

To describe and analyze the fundamental frequency and formants in pitch variation in the /a/ vowel in sopranos.

METHODS

The sample consisted of 30 female participants between the ages of 20 to 45 years without vocal complaints. All sustained vowel sounds were recorded with the /a/ vowel sustained for 5 seconds, with three replications at low (C4-261 Hz), medium (Eb4-622 Hz), and high (Bb4-932 Hz) frequencies that were comfortable for the voice classification. In total, 90 samples were analyzed with digital extraction of the fundamental frequency (f0) and the first five formants (F1, F2, F3, F4, and F5) and manual confirmation. The middle segment was considered for analysis, whereas the onset and offset segments were not considered. Subsequently, FFT (fast Fourier transform) plots, LPC (linear predictive coding) graphs, and tube diagrams were created. The Shapiro-Wilks test was applied for adherence and the Friedman test was applied for comparison of paired samples.

RESULTS

For vocalizations at low and medium pitches, higher values were observed for the first five formant frequencies than for the f0 value. Overlaying the LPC and FFT graphs revealed a similarity between F1 and F2 at the two pitches, with clustered harmonics in the F3, F4, and F5 region in the low pitch. At the medium pitch, there was similarity between F3 and F4, an F5 peak, and tuned harmonics. However, in the high-pitch vocalizations, there was an increase in the F2, F3, F4, and F5 values in relation to f0, and there was similarity between them along with synchrony between f0 and F1, H2 and F2, H3 and F3, H4 and F4, and H5 and F5.

CONCLUSIONS

Pitch changes indicate differences in the behavior of the fundamental frequency and sound formants in sopranos. The comparison of the sustained vowels sounds in f0 at the three pitches revealed specific vocal tract changes on the LPC curve and FFT harmonics, with an extra gain range at 261 Hz, synchrony between peaks of formants and harmonics at 622 Hz, and equivalence of f0 and F1 at 932 Hz.

The Identification of High-pitched Sung Vowels in Sense and Nonsense Words by Professional Singers and Untrained Listeners

High-pitched sung vowels may be considered phonetically "underspecified" because of (i) the tuning of the F₁ to the f₀ accompanying pitch raising and (ii) the wide harmonic spacing of the voice source resulting in the undersampling of the vocal tract transfer function. Therefore, sung vowel intelligibility is expected to decrease as the f₀ increases. Based on the literature of speech perception, it is often suggested that sung vowels are better perceived if uttered in consonantal (CVC) context than in isolation even at high f₀. The results for singing, however, are contradictory. In the present study, we further investigate this question. We compare vowel identification in sense and nonsense CVC sequences and show that the positive effect of the context disappears if the number of legal choices in a perception test is similar in both conditions, meaning that any positive effect of the CVC context may only stem from the smaller number of possible responses, i.e., from higher probabilities. Additionally, it is also tested whether the training in production (i.e., singing training) may also lead to a perceptual advantage of the singers over nonsingers in the identification of high-pitched sung vowels. The results show no advantage of this kind.

The phonological function of vowels is maintained at fundamental frequencies up to 880 Hz

In a between-subject perception task, listeners either identified full words or vowels isolated from these words at F0s between 220 and 880 Hz. They received two written words as response options (minimal pair with the stimulus vowel in contrastive position). Listeners' sensitivity (A') was extremely high in both conditions at all F0s, showing that the phonological function of vowels can also be maintained at high F0s. This indicates that vowel sounds may carry strong acoustic cues departing from common formant frequencies at high F0s and that listeners do not rely on consonantal context phenomena for their identification performance.