Adaptation of singers to physical and virtual room acoustics

International audienceAs observed with instrumentalist musicians, singers are expected to react to variations of the acoustics of the venues where they perform by adapting their voice production. To which extent do these changes happen and how are they related to specific variations of room acoustic conditions? And does it make a difference whether they are physically present in the room or whether the room is simulated electro-acoustically? These questions were addressed by recording two musical solo pieces sung by four singers in eight physical acoustical environments. In addition to close-microphone recordings, binaural room impulse response datasets were measured at the position of the singer in order to reproduce the acoustical space through dynamic binaural synthesis. Room acoustical simulations were performed corresponding to the physical rooms and measurement configurations. The experiment was then replicated in an anechoic chamber where the singers would hear themselves in the various measured and simulated virtual spaces. The performances were analysed through automatic musical feature extraction and statistically related to the room acoustical parameters of each venue by means of mixed regression models. Results revealed statistically significant, but highly individual adaptation strategies, both in physical and virtual environments

How singers adapt to room acoustical conditions

Previous studies on adaptation of performers to room acoustic conditions mostly focused on musicians. The present study deals with the strategies used by singers, whose musical instrument is inherently part of themselves, inducing a specific perception of the sound they produce. To overcome the variations of the acoustical characteristics of the rooms where they perform, singers tend to vary their sound production (e.g. sound intensity, spectral balance, tempo, articulation). To which extend do singers change their sound production when singing in different rooms? The methodology involves 7 rooms with different acoustical characteristics in which 4 singers performed 3 excerpts a capella of musical pieces. In each place, they were recorded by means of nearfield microphone capturing only the singing voice, i.e. without reverberation from the room. Omnidirectional and binaural room acoustic measurements were also performed on stage. Room acoustical parameters are derived from the measured impulse responses and musical descriptors are extracted from each note of the singing recordings, allowing to quantify the musical performances. The degree of correlation between singing and room acoustics is further considered, revealing both common and specific strategies used by the singers

Laser scanning vibrometry and modal analysis to characterize a vocal fold replica

International audienceVocal folds are composed of elastic, soft, multilayer material, and are set to various vibration regimes during phonation, while speaking or singing. To explore such vibration phenomena, a vocal folds replica has been built, allowing to control physical parameters (subglottal pressure, vocal folds stiffness, and glottal aperture) in order to understand their respective contribution. Vocal folds are imitated by latex tubes filled with water under variable pressure. The present study aims at presenting mechanical measurements performed on a single vocal fold replica by means of a shaker provided with an accelerometer in conjunction with a laser vibrometer. This vibration measurement protocol yields a series of frequency response functions over a specific area of the vocal fold. Modal analysis is then performed using an algorithm based on the least square complex exponentials (LSCE) method, which has been developed for single input-multiple output (SIMO) systems. Results are further compared with those from the rational fraction polynomial (RFP) method. Although results are in fair accordance, the observed discrepancies are quantified and discussed

Hydro-elastic finite element model of a vocal fold replica

International audienceExperimental vocal fold replicas are currently used in speech production studies in order to validate simplified models on controllable devices. In addition to in-situ mechanical characterization, it is important to be able to understand their behavior when changing assembly properties or using parameters control to tune the folds, by developing a model able to predict their static and dynamic motions. This also enables to describe more complex vibration behaviors which could be harder to observe experimentally. This paper first presents a hydro-elastic finite element model of a single vocal fold. Numerical results are discussed, along with a parametric analysis. Then this model is extended to take into account the effect of the water pressure on the inflation of the folds and on the resonance frequencies. A hyper-elastic calculation is first used to simulate the latex inflation. An updated Lagrangian approach processes it as a pre-stress term in a modal analysis calculation for the small amplitude vibrations of the hydro-elastic structure, which allows to model the water pressure influence on the mechanical resonances of the simulated replica

Les espaces couplés : comportement, conception et perception dans un contexte de salle de spectacle

This thesis deals with the acoustics of coupled spaces. It is organized along three axes: a physical point of view which considers acoustic fields in stationary and transient conditions, processing of emitted and recorded sound sequences allowing for characterizing the acoustics of such spaces, and finally a perceptual aspect involving the location of a listener. This work aims at providing a more detailed understanding of acoustical phenomena involved in coupled spaces and gives an overall view of the topic through different considerations, from modeling to perception. The study of acoustic fields in coupled spaces was performed by comparing several approaches. Analytical models based on statistical acoustics and diffusion equation were developed and compared with measurements in a scale model at scale 1:20 as well as numerical simulations based on ray-tracing and numerical methods such as the boundary element method (BEM) and finite-difference time-domain (FDTD). Besides, relevant acoustic parameters have been defined, allowing for an accurate description the specifics of decay curves and a semi-automated routine was developed to rapidly analyze both measured and simulated impulse responses. Perception of reverberated sound in coupled spaces is strongly influenced by the multiple sound energy decay rates providing shorter early reverberation as compared to the late reverberation. Two types of perceptual experiments based on listening tests were conducted, one on the ability to discriminate different reverberant environments, the other on the subjective suitability of these different reverberations regarding various musical ensembles.Cette thèse dont le sujet porte sur les espaces couplés en acoustique des salles s'articule selon trois axes : le point de vue mécanique qui considère les champs acoustiques en régime stationnaire et transitoire ; le traitement des signaux émis et enregistrés permettant de caractériser l'acoustique de tels espaces ; et un aspect perceptif adoptant la position d'un auditeur. Ces travaux ont pour objectif d'obtenir une compréhension plus fine des phénomènes acoustiques mis en jeu dans les espaces couplés et de donner un point de vue global sur le sujet, de la modélisation à la perception. L'étude des champs acoustiques dans les espaces couplés a été réalisée en comparant plusieurs approches. Des modèles analytiques basés sur l'acoustique statistique et une équation de diffusion ont été développés et comparés à des mesures sur maquette acoustique à l'échelle 1:20, à des simulations numériques basées sur le principe du lancer de rayons ainsi qu'aux méthodes ondulatoires d'éléments frontière (BEM) et de différences finies en domaine temporel (FDTD). Par ailleurs, des indices acoustiques ont été définis, décrivant précisément les spécificités des courbes de décroissance et un code de traitement semi-automatisé a été réalisé afin d'analyser les réponses impulsionnelles. La perception du son réverbéré dans les espaces couplés est fortement influencée par les taux de décroissance multiples de l'énergie sonore. Deux types d'expériences perceptives basées sur des tests d'écoute ont été menées, l'une sur la capacité de discrimination de différents environnements réverbérants, l'autre sur l'adéquation subjective entre ces réverbérations et différents ensembles musicaux

Pilot study on the influence of spatial resolution of human voice directivity on speech perception

A perceptual threshold related to spatial resolution of the human voice directivity was determined through a listening test of similarity (MUSHRA). Directivity data of an artificial talking head measured at high spatial resolution (spherical harmonics order 35) was the input of a room acoustics simulation software (RAVEN) to build sound stimuli in various room acoustic conditions and source–receiver arrangements, with different voices. Results showed that, at spherical harmonics order 8 and above, the voice signal was not anymore perceived as significantly different from the greatest resolution. An analytical model was proposed and showed good agreement with the listening test results

Effet des jalousies du récit d’orgue comme moyen d’expressivité musicale

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Changes in the voice production of solo singers across concert halls

International audienceTo investigate the influence of room acoustics on singing, four lyrical singers (soprano, mezzo-soprano, tenor, baritone) performed four musical pieces in eight different venues (from dry studio to reverberant church). In addition to vocal intensity measured by a near-field microphone, glottal behavior (vibratory fundamental frequency and contact quotient) was assessed by electroglottography. Statistical linear mixed models showed that the variance in vocal performance was partly explained by room acoustics. Complementary to previous results on voice musical features influenced by timbre and level of the room's response, voice production parameters were mostly influenced by spatial aspects of the room's response

Physical modelling of voice pathology induced by a growth on the vocal folds

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