Blend in Singing Ensemble Performance: : Vibrato Production in a Vocal Quartet

Objective ‘Blend’ is a defining characteristic of good vocal ensemble performance, and in order to achieve this directors often identify vibrato as a feature to be controlled and consequently restrict its use. Analysis of individual voices in ensemble situations presents several challenges, including the isolation of voices for analysis from recordings. This study considers vibrato production as a feature that contributes to blend through an ecological study of a vocal quartet. Method / Design An SATB vocal quartet was recorded using head-worn DPAs (miniature microphones) and electrolaryngograph electrodes to enable fundamental frequency analysis of the individual voices. The same four-part material was recorded over several weeks of rehearsal to allow analysis of conscious and subconscious changes to vibrato production over time. Alongside the recording of their rehearsal discussions, singers were also asked for opinions of vibrato production in connection with blend. Results / Conclusions The results indicate that the singers in this study adjusted their vibrato to some extent to improve blend, with some instances of synchrony between voice parts. Some conscious alterations to vibrato were made to improve blend, however these are not always evident in the data, suggesting that these singers’ own perceptions of their performance may have be influenced by other factors. These findings indicate a need for further studies of vibrato as a feature of blend, particularly in terms of the synergies between expectation and actual production, and potential synchronicity between singers: increased understanding of vibrato in an ensemble setting will lead to more efficient rehearsal techniques and vocal training, and could prevent vocal misuse leading to pathology in the future

Distinguishing characteristics of vocal techniques in the specialist performance of early music

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Diphthong Synthesis Using the Dynamic 3D Digital Waveguide Mesh

Articulatory speech synthesis has the potential to offer more natural sounding synthetic speech than established concatenative or parametric synthesis methods. Time-domain acoustic models are particularly suited to the dynamic nature of the speech signal, and recent work has demonstrated the potential of dynamic vocal tract models that accurately reproduce the vocal tract geometry. This paper presents a dynamic 3D digital waveguide mesh (DWM) vocal tract model, capable of movement to produce diphthongs. The technique is compared to existing dynamic 2D and static 3D DWM models, for both monophthongs and diphthongs. The results indicate that the proposed model provides improved formant accuracy over existing DWM vocal tract models. Furthermore, the computational requirements of the proposed method are significantly lower than those of comparable dynamic simulation techniques. This paper represents another step toward a fully functional articulatory vocal tract model which will lead to more natural speech synthesis systems for use across society

Resonance Tuning in Three Girl Choristers

Objective The phenomenon of resonance tuning, whereby a singer modifies the shape of their vocal tract to increase the acoustic power output, is commonly exploited across large pitch ranges by professional sopranos and has been observed to a lesser degree in nonexpert adult singers. This study considers the employment of two common resonance tuning techniques in experienced child singers; tuning the first vocal tract resonance to the fundamental (R1: fo) and tuning the second resonance to the second harmonic (R2:2 fo). Methods Wide-band excitation at the subject's mouth during singing was used to measure the vocal tract resonances of three girl choristers, and vowel formant values in speech were extracted from samples of spoken text. Measured resonance values were cross-referenced with first and second harmonics for sung vowels across the subjects' ranges to identify the resonance tuning techniques employed, and these results were compared with those previously observed by others in professional adult classical singers. Results and Conclusions There was clear evidence that the subjects employed resonance tuning techniques comparable with the strategies used by adult singers. The protocol and results presented here pave the way for further studies exploring the development of resonance tuning techniques in young soprano voices, with the potential to impact on approaches to classical singing training in the future

Impact Thresholds of Parameters of Binaural Room Impulse Responses (BRIRs) on Perceptual Reverberation

This paper presents a study on the perceived importance of different acoustic parameters of Binaural Room Impulse Response (BRIR) rendering. A headphone-based listening test was conducted with twenty expert participants. Three BRIRs generated from simulations of three different rooms were convolved with a dry speech signal and used as reference audio samples. Four BRIR parameters, Initial Time Delay Gap (ITDG), Forward Early Reflections (FER), Reverse Early Reflections (RER) and Late Reverberation (LR) were systematically altered and convolved with a speech signal to generate the test conditions. A staircase method was used to obtain the threshold at which each BRIR parameter was perceived as different from the reference audio sample. The average perceived impact threshold of each parameter was then calculated across the twenty participants. Results show that RER removal and ITDG extension have a clear impact on the perceptual reverberation of speech audio. Subjects were less sensitive to FER removal. The effect of LR removal on perceptual reverberation is hard to distinguish. Therefore, RER and ITDG are of particular importance when designing artificial reverberation algorithms, whilst more research is needed to understand the perceptual contribution of LR. Minor changes in FER and LR are less significant

BabblePlay : An app for infants, controlled by infants, to improve early language outcomes

This project set out to develop an app for infants under one year of age that responds in real time to language-like infant utterances with attractive images on an iPad screen. Language-like vocalisations were defined as voiced utterances which were not high pitched squeals, nor shouts. The app, BabblePlay, was intended for use in psycholinguistic research to investigate the possible causal relationship between early canonical babble and early onset of word production. It is also designed for a clinical setting, (1) to illustrate the importance of feedback as a way to encourage infant vocalisations, and (2) to provide consonant production practice for infant populations that do not vocalise enough or who vocalise in an atypical way, specifically, autistic infants (once they have begun to produce consonants). This paper describes the development and testing of BabblePlay, which responds to an infant’s vocalisations with colourful moving shapes on the screen that are analogous to some features of the infant’s vocalization including loudness and duration. Validation testing showed high correlation between the app and two human judges in identifying vocalisations in 200 minutes of BabblePlay recordings, and a feasibility study conducted with 60 infants indicates that they can learn the contingency between their vocalisations and the appearance of shapes on the screen in one five minute BabblePlay session. BabblePlay meets the specification of being a simple and easy- to-use app. It has been shown to be a promising tool for research on infant language development that could lead to its use in home and professional environments to demonstrate the importance of immediate reward for vocal utterances to increase vocalisations in infants

The Perception of Formant Tuning in Soprano Voices

Abstract 0.1. Introduction At the upper end of the soprano singing range, it is known that singers alter the shape of their vocal tracts in order to bring one or more of the vocal tract resonances nearer to a harmonic of the voice source; a process known as resonance tuning, which increases the amplitude of the sound produced with little eort from the singer. This study investigated the perception of first and second resonance tuning; key strategies observed in classically trained soprano voices. It was expected that the most commonlyused strategies observed in singers would be preferred by the listeners, and since previous investigations have often focussed only on a single vowel sound (usually /A/), this test will also allow for comparison of dierent tuning strategies between vowels. 0.2. Method Synthetic vowel sounds were generated using an L-F glottal flow model, passed through a series of filters to represent the vocal tract resonances. Listeners then compared the sounds, which included 3 vowels, at 4 fundamental frequencies ( f0), to which 4 dierent tuning strategies were applied; (A) the expected formant values in speech, (B) the first formant tuned to the fundamental, (C) the second formant tuned to the second harmonic, and (D) both first and second formants tuned to the first and second harmonics respectively. Participants were asked three sets of questions: comparing how much they preferred dierent tuning strategies, how natural they found dierent tuning strategies, and identifying the vowel of each sound. 0.3. Results The results obtained varied greatly between vowels; the results for the /A/ vowel were similar for preference and naturalness, but no clear pattern was seen for vowel identification. The results for the /u/ vowel did not appear to show a clear dierence between the dierent tuning strategies for preference, and only a little separation for naturalness. The vowel identification was generally very poor for this vowel. The results for the /i/ vowel were striking, with strategies including R2 tuning both preferred and perceived as more natural than those without for both preference and naturalness, however for the vowel identification, strategies without R2 tuning were most often correctly identified. 0.4. Conclusion The results indicate that the perception of dierent tuning strategies alters depending on the vowel and the perceptual quality investigated (preference, naturalness, or vowel identification), and whether the first and second harmonic fall above or below the first or second formants. For some vowels and perceptual qualities, formant tuning was found to be beneficial at lower f0 values than expected based on current expectations of formant tuning in practice