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cote interne IRCAM: Eveno13a; None / None; National audience; Toneholes have an important role in the acoustics of woodwind instruments. In the saxophone, the toneholes are surmounted by a key provided with a pad and what musicians and artisans refer as a “resonator”. They are flat disks made of metal or plastic fixed in the middle of the pad and are called with the acoustically neutral term “cover” in the article. In order to understand their role, measurements of the input impedance of a cylinder topped by a key with interchangeable pads (with and without covers) are performed. For closed holes, pads with covers have a low absorption coefficient; for open holes, effects of the covers on the radiation are highlighted when the key is at a small height. An analysis of the vibrations of the pads shows that these effects can be explained by the high mobility of the pads without a cover, which seems to act as a stiffener. Then, the input impedance measurement of an entire saxophone confirms that, when the holes are closed, the effect of a pad without a cover is to increase the damping. The effect on open holes is close to negligible. Finally, measurements in playing situations show that saxophones without covers have higher harmonic spectral centroids and require greater mouth pressure.

cote interne IRCAM: Lopes13a; None / None; National audience; This paper deals with a robotized arti?cial mouth adapted to brass instruments. A technical description of the robotic platform is drawn, including calibrations, initialization processes, and modes of control. An experimental protocol is proposed and the repeatability is checked. Then, experiments are conducted on a trombone for several types of quasi-static controls. Sound descriptors (fundamental frequency, roughness, energy) of measured acoustic signals are estimated and used to build cartographies indexed by the control inputs. An analysis reveals that several stable notes can easily be reached using a basic mapping with respect to these control inputs. However, the histogram of fundamental frequencies shows that input impedance peaks in the high range of the instrument do not correspond to notes that can be played by the arti?cial mouth, contrarily to musicians. It also reveals that some notes are dif?cult to play in the middle range. This exploration suggests some possible improvements of the machine that are ?nally discussed.

cote interne IRCAM: Meurisse13a; None / None; National audience; Active control is widely used in industry. However, there have been relatively few applications to musical instruments, particularly wind instruments. The aim of this study is to attempt to control the sound quality and playability of wind instruments, using active control. Active control makes it possible to modify the input impedance (amplitude and frequency) of an instrument and to modify the instrument's quality. Simulations and first experiments on a cylindrical tube, which is considered to be a simple wind instrument, with embedded microphone and speaker are presented. Finally, the effects on the sound and the input impedance of the instrument are studied.

cote interne IRCAM: Bianco12b; None / None; National audience; Trumpet performance builds on the synergy of multiple factors. From a physiological point of view, the production of a simple musical tone relies on the control of the pressure at the lips, the contact force on the mouthpiece, and the oral articulatory gestures and configurations. Whereas previous studies described the magnitude of these control parameters in quasi-static regime of oscillation, the present investigation focuses on their temporal evolution and interrelation. Intra-oral pressure, mouthpiece force, facial muscular activity of two group of muscles, and the radiated sound were recorded from three professional players performing isolated and articulated tones with three different dynamics. Results showed that the experimental conditions affected the amount and location of variability in the performance, and the behavior of intraoral pressure at note initiation. All together, this suggests that different dynamics and sequencing may cause a reorganization of the mechanisms underlying the production of a tone.

cote interne IRCAM: Helie11a; None / None; National audience; In simple models of brass instruments (trumpet, trombone, etc.), important control parameters include the pressure in the mouth, the force applied by the mouthpiece on the lips and parameters which characterize the lips such as equivalent masses, dampers and stiffnesses (this is usually called the "mask" of the performer). It is easy to measure the pressure in the mouth during performance but not to access to other control parameters. This problem is similar for the voice (and multiplemass models of vocalfolds): in this case, the oscillating exciter becomes the vocalfolds rather than the lips and the resonator is the vocal tract rather than the trumpet. In order to have a reproducible and controllable experimental tool, the automation of an artificial mouth dedicated to the playing of brass instruments was made at IRCAM in the project of the National Research Agency CONSONNES (2005/2009, http://www.consonnes.cnrsmrs.fr), with the assistance of the Ecole des Mines de Paris, and BTS students. The actuators of the robot are: (A1) a solenoid valve controlling the air supply, (A2) a moving coil which allows to translate the artificial mouth and to monitor the lips force applied to the mouthpiece, (A3-4) two actuators controlling the volume water in each of the lips (latex chambers filled of water). The sensors used for measurements are: (S1-2) high precision pressure sensors (one in the mouth, one in the mouthpiece), (S3) an optical sensor measuring the opening between the lips, (S4) a force sensor (lipsmouthpiece), (S5-6) water pressure sensors (one in each lip). A few additional sensors are used for base controls (position sensors (S2bis-S4bis) of actuators (A2-4)) and to check experimental conditions (temperature and high pressure sensor for the air supply). Preliminary results and confrontations between theoretical models and experimental data has yet been obtained in [1,2] using this tool and a similar more advanced work has been performed on the clarinet in [3]. In this presentation, the current features of the robotized artificial mouth will be presented. First, basic mappings between the position of actuators (A2-4) and force or pressure signals (S45) are analyzed. This is used to calibrate the lips and to configure the machine as a testbed. Second, slowly timevarying commands are used to monitor the lips and to obtain sounds and quasistationary regimes. This makes appear various kind of regimes (non oscillating, quasiperiodic, nonperiodic, etc). Third, a sound analysis is processed to generate cartographies of sound descriptors such as energy, fundamental frequency (if any), sound ruggedness (etc) with respect to the quasi-static commands. This exploratory tool can be used to perform simplified and systematic analysis such as in [4]. Finally, although measures highlight hysteresis phenomena, the (complex) cartographies of regimes are sufficient to build some basic melodies (similar to those played by a novice unskilled players) during which all the signals of sensors (S1-6) can be recorded and analyzed. One possible evolution of such an exploratory tool could consists of adapting the mechatronics instruments to the case of artificial vocal folds and vocal tracts.

cote interne IRCAM: Hezard11b; None / None; International audience; Le paradigme source-filtre est l'approche la plus répandue au sein de la communauté scientifique pour établir des méthodes d'analyse et de synthèse de la voix. Or, si les modèles source-filtre sont peu gourmands en puissance de calcul, ils ignorent des phénomènes indispensables pour obtenir des sons naturels. La démarche adoptée dans notre travail est de modifier le modèle source-filtre classique afin de prendre en compte un couplage aéroacoustique simplifié entre les cordes vocales et le conduit vocal tout en gardant les avantages des modèles source-filtre, à savoir un coût de calcul réduit et des méthodes d'analyse efficaces. Dans ce but, nous établissons un modèle de production vocale basé sur un modèle de fonction d'aire glottique. Une étude menée sur une base de données de fonctions d'aire glottique extraites de vidéo-endoscopies ultra-rapides du larynx montre que le modèle Liljencrants-Fant (modèle LF), bien qu'ayant initialement été développé comme un modèle de débit glottique, se révèle tout aussi pertinent pour modéliser les fonctions d'aire glottique. Ce modèle d'ouverture glottique 1D simplifié, couplé à des équations standards de Bernoulli sous hypothèse quasi-stationnaire et à une pression subglottique (constante ou variable) nous permet de construire un modèle de source glottique à géométrie forcée, par opposition aux modèles source-filtre classique qui sont à acoustique forcée. Le couplage entre la source glottique et le conduit vocal est assuré par la continuité du débit et de la pression acoustiques à l'interface entre la glotte et le conduit vocal. Enfin, le conduit vocal est modélisé par une habituelle concaténation de cylindres dans lesquels les ondes se propagent en ondes planes et sans pertes. Le modèle est alors piloté par la pression subglottique, la fonction d'aire glottique et la géométrie du conduit. Des exemples de synthèse, d'analyse et de transformation de signaux de voix nous permettent d'évaluer les performances de notre modèle en comparaison avec un modèle source-filtre classique développé à l'IRCAM.

cote interne IRCAM: Causse11a; None / None; National audience; The quality of a musical instrument embraces many aspects such as tuning, ease of play, tone, etc. This study aims to validate the use of the sum function (SF) proposed by Wogram from the measurement of input impedance as a descriptor of quality. This work is part of a wider project, PAFI (Aid Platform for Instrumental Making), supported by the French National Agency of Research. To validate the choice of the SF, we created a family of trumpets made from a basic instrument for which the leadpipe will be slightly modified for each model. The SF was calculated for a range of selected frequencies from the measurement of the input impedance of these different trumpets. The next step was to ask musicians experts to play these instruments, to measure the playing frequencies, and to note their feedback about quality. These tests were supplemented by comparative tests carried out this time with the help of a robotic artificial mouth. The final step involved was to try to identify correlations between the SF and the results of various tests and propose correction factors to be made to the formula of the SF, related to the nuance or range for example.

cote interne IRCAM: Hezard10b; None / None; International audience; Les outils d’analyse et de synthèse de la voix suscitent beaucoup d’intérêts et s’intègrent dans de nombreuses applications. Afin de répondre à la complexité des phénomènes mis en jeu dans sa production, la communauté scientifique s’intéresse à des approches fondées sur (1) la concaténation d’unités de sons, (2) des modèles de signaux, (3) la modélisation source-filtre, (4) des modèles physiques simplifiés, (5) des modélisations vibro-aéroacoustique complexes. Les approches de type signal (1-3) permettent des analyses/synthèses de qualité et les approches plus physiques permettent de mieux comprendre le fonctionnement de la voix. Cependant, le réalisme sonore est encore limité dans le cas des modèles de signaux car des phénomènes significatifs (e.g. couplage glotte/conduit vocal) ne sont pas représentés et il est difficile d’obtenir des méthodes d’estimation et d’inversion robustes pour les modèles physiques. On se propose ici de construire, d’étudier et de valider des systèmes dynamiques de production de la voix hérités de la structure source-filtre mais intégrant l’effet de la géométrie de la glotte et du couplage avec le conduit vocal; on se situe à l’interface entre (3) et (4). Le projet s’articule en trois parties: 1. Des modèles à pilotage forcé hérités du « modèle source-filtre » mais incluant des phénomènes physiques négligés dans les versions initiales (tels que couplage aéro-acoustique) seront proposés et étudiés. Dans un premier temps, le modèle standard de Liljencrants-Fant sera utilisé. Il pilotera l’ouverture d’un modèle géométrique de glotte plutôt que directement son débit glottique. 2. Un dispositif électronique d’électroglottographe multi-capteurs à multiplexage fréquentiel sera développé dans le cadre d’un projet mécatronique de l’Ecole des Mines de Paris, Mines’ParisTech. 3. Des outils d’estimation automatique des paramètres de pilotage seront développés pour chaque modèle afin d’aboutir à une chaîne complète d’analyse-resynthèse de son.

cote interne IRCAM: Zelmar07a; National audience; The quality of sound in terms of duration and level is not satisfactory in the high register of the piano, and unlike the other registers, dampers are not necessary. This problem is related, mainly, to the coupling between the strings, the bridge, and the soundboard. To enhance the tonal quality of this register, some piano makers add extra sound produced by the oscillation of the short rear section of strings, properly tuned (octave, fifth or unison) in line with the vibrating section and driven by the latter through the bridge (this is called ”duplex scale”). To analyze the effect of the ”duplex scale”, experimental and theoretical studies were carried out on a real piano and on an individual sample of a Grand Piano built by the Tallinn Piano Factory for A. Stulov of the Institute of Cybernetics, specially prepared for experimental measurements. Inspired by the model of nonconservately coupled oscillators of G. Weinreich (J. Acoust. Soc. Am. 62, N 6, 1977), extended to a third oscillator, we investigate the energy transmission between the string coupled through the bridge and analyze the effect of the ”duplex scale” in the high register. Results will be presented and discussed. [Support from Egide-Parrot program, project N 82/239584, is acknowledged].

cote interne IRCAM: Cuenca07a; None / None; National audience; A model of the vibrational coupling between the strings, the bridge and the soundboard of the piano in its treble register is presented. Each one of these vibrating structures is separately described by its mechanical input admittance matrix in which the nine terms represent impulse responses or frequency responses to a vectorial input force. The total admittance matrix is analytical and is calculated by assembling the latter in accordance with classical mechanical continuity equations. This formalism allows to study the role of each part of the system by simulating the interaction between a chosen number of structures. Simulations show that the two perpendicular polarisations of bending motion of a single string influence each other due to the elastic response of the bridge. Similar to this is the coupling between unison strings. These interactions give rise to beats and double decay phenomena, which are of particular interest to professional piano makers and tuners. The influence of sound radiation by the soundboard and of duplex strings on the temporal behaviour of the piano and on the spectral content of vibrations is discussed as well. Simulations will be presented and discussed comparing them to experimental work carried on a simplified piano.

cote interne IRCAM: Petiot07a; None / None; National audience; This paper addresses the characterisation of cello sounds. In order to study to which extent a jury perceives differences between two cellos in playing conditions, we carried out two blindfolded hearing tests, involving two instruments and two professional musicians: (1) An evaluation test of the couple musician-instrument on a structured scale, for 5 different attributes defined by adjective-pairs. The assessment of the jury was based on the same musical sequences, played by the musicians; (2) A comparative test, based on the ranking of the couple musician-instrument on 4 different attributes. The same short musical fragment was played successively by the musicians. All the played musical sequences have been recorded, and metrics based on the acoustic signal (playing frequency, spectral centroid, signal/noise ratio) were calculated in order to interpret the perceived differences. The results show that for the evaluation test, the inter-subject differences of the jury are too large and do not allow the definition of a significant instrument effect. For the comparative test, the agreement between the subjects is better and significant differences between the instruments and the musicians can be observed, explained by the signal processing of the played sounds.

cote interne IRCAM: Demoucron07a; None / None; National audience; Sound synthesis of bowed strings instruments using physical models offers the possibility of simulating the vibration of the string from the main parameters controlled by the violinist: bow pressure, bow velocity and position on the string. A specific study of gestures that are performed on real instruments would improve the realism of these devices and would make them easier to use. After a brief description of the physical model that has been used during this work, we will present some setups dedicated to the measurement of the gesture parameters applied by the violinist. The data collected from different bowing techniques such as tremolo, spiccato, détaché or martelé permit to extract characteristic features and to build parametric gesture patterns that can be used to control the physical model.

cote interne IRCAM: Demoucron06a; None / None; International audience; Un dispositif est présenté qui permet la mesure de la pression exercée par l'archet sur la corde, dans une situation de jeu réel. L'utilisation conjointe de la mesure obtenue et d'autres dispositifs pour la mesure de la vitesse, permet de contrôler un modèle physique de corde frottée afin d'obtenir une synthèse sonore réaliste du violon.

cote interne IRCAM: Causse06a; None / None; National audience; De tout temps, les instruments de musique ont évolué pour répondre à la demande des musiciens, compositeurs ou interprètes. Après la création de l'instrument et la découverte par le compositeur, la musique s'adapte puis échappe bien souvent à l'instrument. Alrs, ce dernier évolue ou disparaît. Aujourd'hui, la micro-informatique offre de nouvelles possibilités : les instruments virtuels. Certains, que l'on présente ici, sont issus d'études sur le fonctionnement des instruments de musique réels.

cote interne IRCAM: Fritz05b; None / None; National audience; This study investigates acoustical features of the vocal tracts of the clarinettists, and how these features influence the frequency of the note plaed, its spectrum and the mouth pressure required to initiate the note. Experiments were conducted using a blowing machine with an artificial VT. Threshold pressures, playing frequencies, spectra and transition transients were measured. The configuration

cote interne IRCAM: Causse05b; None / None; National audience; Si l'on est en mesure d'expliquer leur fonctionnement, on est encore loin de pouvoir caractériser et comparer en termes scientifiques la différence de qualité entre deux violoncelles.

cote interne IRCAM: Causse04a; None / None; National audience; As for many instrumentalists, didgeridoo players seem to rate the quality of the instrument according to the tonal qualities and the playing properties. Our study is carried out in a preliminary and prospective way on a serie of eight instruments chosen by the players, in a corpus of around fifty instruments, for their diversity of qualities and geometries. The study includes an experimental procedure (tests with two players, joint authors of this study) and a geometrical and physical analysis of the instruments and emitted sounds. Some first correlations between the geometrical and physical properties of the same instrument, the nature of the emitted sound and the quality perceived by the players will be presented or proposed.

cote interne IRCAM: Fritz03b; None / None; National audience; Previous studies (Mooney Benade, Hoekje) confirm musicians' opinions that the vocal tract affects both timbre and pitch. Jhnston, Troup and Clinch modelled the tract as a one peak resonator, which, if tuned tuned to the fundamental f0 of the clarinet, gives a playing frequency of f0. But this result depends upon their particular tract impedance Z, which is small and real ar harmonics of f0. In general, the playing frequency is shifted. We relate the flow and the pressure difference at the reed by the usual non linear Bernouilli' equation in the time domain, simplified as a third order polynomial. In the frequency domain, the impedances of the clarinet and the vocal tract are in series. To obtain an analytical result for the frequency shift, we expand about the threshold oscillation. We compare this result with numerical results from the harmonic balance method. Finally, impedance spectra measured on an artificial VT with a discrete but variable area function are used in this theoretical study. We suggest that tuning the vocal tract to f0 may be rare and unnecessary.

cote interne IRCAM: Otondo02a; None / None; National audience; Measurements of the directivity of musical instruments are presented in the context of a new directivity representation of sources for auralizations. Three instruments have been recorded over the whole compass simultaneously in both horizontal and vertical planes with a multi-microphone array. Results are analyzed focusing on the differences between the directivity of particular tones and the averaged directivity over the whole compass. The consequences of these variations in a real performance situation in a room are looked into using computer room simulations. Further developments will consider room auralizations using different representations for the directivities of musical instruments.

cote interne IRCAM: Ricot02a; None / None; National audience; The accordion reed is an example of a blown closed free reed. Unlike most of oscillating valves in wind musical instruments, self-sustained oscillations occur without acoustic coupling. Flow visualizations and measurements in water show that the flow can be supposed incompressible and potential. A model is developed and the solution is calculated in the temporal domain. The excitation force is foud to be associated with the intertial load of the upstream fluid. Inertial effect leads to velocity fluctuations in the reed opening and then to an unsteady Bernouilli force. A pressure component generated by the local reciprocal air movement around the valve is added to the modeled aerodynamic excitation pressure. Since the model is two-dimensional, only qualitative comparisons with air measurements are possible. The agreement between the simulated pressure waveforms and measured pressure in the very near field of the reed is reasonable. In addition, an aeroacoustic model using the porous Ffowcs Williams-Hawkings integral method is presented. The integral expressions of the far field acoustic pressure are also computed in the temporal domain. In agreement with experimental data, the sound is found to be dominated by the dipolar source associated by the strong fluid velocity fluctuations in the plane of the reed.

cote interne IRCAM: Misdariis00a; None / None; International audience; Un modèle physique non-linéaire d'auto-oscillation de l'anche d'accordéon est proposé pour des applications en synthèse sonore. Ce modèle est dérivé de l'étude expérimentale in vitro de la lame et de la caractérisation de la gométrie de l'écoulement par visualisation dans l'eau. Deux régimes d'auto-oscillation sont observés se caractérisant par deux lois d'évolution différentes de la fréquence en fonction de la pression d'alimentation. Il est mis en évidence que la force d'excitation de la lame est créée par les effets d'inertie du fluide présent en amont de la lame et non par les instabilités turbulentes du jet. Le modèle permet de reproduire les comportements caractéristiques des lames observés lors de l'étude expérimentale et de synthétiser des sons de lames d'accordéon d'un grand réalisme.

cote interne IRCAM: Houix01a; None / None; International audience; None

cote interne IRCAM: Msallam00c; /; National audience; In this paper we present a simple physical model of the trombone reproducing the generation of brassy sounds for loud tones. Two implementations are considered for the nonlinear wave propagation effects: one in which these effects only affect the radiation of sound, the other in which they also take part in the oscillation process. We explain the different hypotheses which lead to these different models and compare the numerical results they give.

cote interne IRCAM: Causse00a; None / None; National audience; Study on double decay of individual partials of piano sound

cote interne IRCAM: Causse99a; /; National audience; The accordion is a free-reed instrument. The two identical reeds associated with one note are driven separately by the airflow created by the inward and outward movements of the bellow. In this present study, attention is focused on understanding the aerodynamic phenomena involved in reed vibration. The acoustical model is deduced from the variation of the flow rate through the slot in the reed plate. A variety of laboratory measurements and observations on different accordion reeds have been made with defferent blowing pressures. Among them : near-field sound pressure (microphones above and under the reed); displacement and velocity of the reed (capacitive sensor and laser vibrometer system); reed profile, magnified stroboscopic images, flow visualization; etc. From these experimental results, we have extracted the most important phenomena involved, which are to be implemented in a physical model accurate enough to describe the behavior of the reed and to reproduce its characteristic sound. This physical model must be as simple as possible to be computationally efficient and usable in sound synthesis. For example, at Ircam, it is possible to program the accordion model in Modalys, a synthesizer language based on modal representation formalism. Similarities and differences between simulated and real sounds will be discussed.

cote interne IRCAM: Houix99a; /; National audience; The present study sought to understand the acoustic cues and perceptualprocesses involved in categorizing metal bars on the basisof cross-sectional geometry in spite of their being struck in several places, creating large within-bar acoustic differences.We also investigated the influence of experimental instructionson the kinds of acoustic information selected by listeners to perform the task.

cote interne IRCAM: Causse99b; /; National audience; Judgment of musical instrument quality is a complex process that implies criteria relating to the nature of the sound produced (accuracy, timbre, ...) but also sensations closely linked to the contact between the instrument and the musician (ease of playing,...) byt also sensations closely linked to the contact between the instrument and the musician (ease of playing, ...). From this viewpoint, a set of trumpets was studied (Causse and al, (1995) ): from playing tests carried out by professional trumpet players, attempts were made, on the one hand, to define subjective factors they used in their judgments and, on the other hand to correlate these factors with geometrical or acoustical parameters. This preliminary study led to three notions implied in this judgment process, among which was the sound volume, and to propose, for each of them, a significant physical interpretation. Following this study, the sound volume, which is an important component of the trumpet player's vocabulary and which seems to be associated with a broader notion of openness, was focused on. Different possible interpretations of openness, through a questionnaire, followed by an experimental procedure (playing and hearing tests), were explored. In addition, complementary measurements were done in order to propose a more precise physical interpretation. The first results obtained from the second study will be presented and discussed.

cote interne IRCAM: Thomas98a; National audience; A characteristic of the piano tones is their double decay (the initial sound followed by the " aftersound "), related to the existence of two polarizations. The goal of this study is to understand and to compare more quantitatively than the previous work, the influence of parameters which are under the control of the piano tuners: the mistuning and irregularities)n striking action of the hammer. We simulated on a computer the vibration of an unison group of strings, which includes the dominant damping at the bridge as well as the vertical coupling between strings. Excitation irregularities were simulated by varying the initial displacement and velocities of the strings. The study analyses the ratio of the aftersound to the immediate sound, the compound decay, and the amount of destructive interference. This interference can be seen where the slope of the decay curve changes, and is most pronounced at the bridge, where the strings are dynamically coupled. This comparison leads to the conclusion that if necessary, the piano tuner can to a certain extent correct for a poorly adjusted hammer by modifiying the mistuning. But all hammers properly adjusted are essential for a constant and uniform level for all notes, which is necessary for a very good piano.

cote interne IRCAM: Iovino97a; /; National audience; The originality and flexibility of the physical modelling synthesizer Modalys is being continously validated by an ever-growing communityof users made up by composers, acousticians and musicologists alike.In this paper we will present the main lines that have oriented recent research around Modalys. These can be summarized: (1) Exploration and tentative classification of the musical possibilities of Modalys. (2) Use of modal synthesis as a meeting point betweensignal synthesis and physical modelling synthesis. (3) Port of Modalys to a real-time platform.

cote interne IRCAM: Causse97a; /; International audience; [FRANCAIS] : La qualité d'un instrument de musique, perçue par celui qui le joue, est le résultat d'un jugement très complexe suivant plusieurs aspects (critères) d'appréciation subjective. L'objectif de cette étude est de tenter d'établir des relations entre ces critères et des grandeurs physiques mesurables, caractérisiques de l'instrument. L'étude s'articule autour de deux axes : des tests subjectifs suivis d'une analyse, et des mesures physiques. Pour la partie subjective, nous avons choisi une approche neutre pour laquelle les sujets (trompettistes professionnels) doivent évaluer la dissimilarité de plusieurs instruments haut-de-gamme présentés par paires successives. Les données obtenues sont traitées avec EXSCAL, méthode d'analyse multidimentionnelle, qui nous fournit un espace perceptif commun à tous les instrumentistes. Les mesures physiques sont de deux types : relevés géométriques sur les différentes parties de l'instrument (longueur, diamètres, épaisseur des parois, etc.) et mesures acoustiques, à la fois dans le domaine fréquentiel (impédances d'entrée) et dans le domaine temporel (réponses impulsionnelles). A partir de ces données physiques, plusieurs paramètres sont calculés (fréquence des résonnances, facteurs de qualité, enveloppes spectrales, etc.). L'étape suivante consiste à corréler les axes de l'espace perceptif, nommés par des termes empruntés au vocabulaire des musiciens recueilli au cours d'un deuxième test "informel", avec les critères objectifs précédents. Au final, l'examen des résultats fait apparaître une corrélation assez élévée entre chacune des dimensions perceptives et un paramètre physique influent : la largeur du son avec un facteur de qualité, la touche avec le diamètre moyen de la branche (partie de la trompette en amont des pistons) et la facilité de jeu avec un paramètre d'inharmonicité. L'ensemble des résultats et les perspectives de cette étude seront présentés et discutés. [ANGLAIS] : Musical instrument quality, perceived by the player, is the result of a complex judgement according to many subjective criteria. The aim of this study is to try to make relations between these criteria and some measurable physical parameters that are specific to the instrument. The study is built around two approaches : subjective experiments (dissimilarity judgement followed by a multidimensional analysis) that give us a perceptual space and physical measures (geometric and acoustic). When we try to link these two, we find that each of the perceptual dimensions is well correlated with an important physical parameter : the sound volume with a quality factor, the touch with the mean diameter of the branch and the playing ease with an inharmonicity parameter.

cote interne IRCAM: Msallam97a; /; International audience; We propose a quasi monodimensionnal model for propagation of nonlinear acoustics waves in pipes including viscothermal boundary layer effects using an integral method analogous to those used in aerodynamics. We present some numerical computations on simple cases and an original one, thenonlinear propagation effect in a trombone.

cote interne IRCAM: Verge97a; /; National audience; A simple one-dimensional representation of recorderlike instruments, that can be used for sound synthesis by physical modeling of flutelike instruments, is presented. This model combines the effects on the sound production by the instrument of the jet oscillations, vortex shedding at the edge of the labium, and turbulence in the mouth of the instrument. The jet oscillation model used is a modification of the semi-empirical model by Fletcher [J. Acoust. Soc. Am. 60, 926-936 (1976)]. The steady-state drive of the acoustical oscillations in the pipe by the jet motion is represented by a pressure jump in the mouth of the instrument. Vortex shedding at the edge of the labium during steady-state operation is taken into account by the use of a free-jet model. The combined effects of this nonlinearity and the jet-drive model enable one to correctly predict the steady-state amplitude of the fundamental. The turbulence noise source is represented by an additional pressure jump across the mouth of the instrument having an amplitude scaling with the square of the jet velocity. This simple model appears to correctly predict the noise level and its spectrum, both with and without oscillations of the jet. The transient response of the model is triggered by the initial volume injection into the mouth of the instrument and is dependent on the steepness of the driving pressure rise.

cote interne IRCAM: Lakatos97a; None / None; National audience; The representation of auditory source characteristics

cote interne IRCAM: Msallam97b; /; National audience; In this paper we propose a physical model of the trombone including nonlinear propagation effects. Theoretical analysis and numerical simulations are presented. We then deduce simple models for sound synthesis.

cote interne IRCAM: Causse96a; /; National audience; Nous avons eu l'occasion de rencontrer Dominique Buisson au sujet d'une des flûtes de la grotte d'Isturitz (fig. 1). Soucieux d'approfondir ses recherches, il nous avait contactés afin d'essayer d'apporter à cet instrument les éléments complémentaires à son étude. C'est ainsi que nous nous étions réunis à l'IRCAM, au Musée des Antiquités Nationales de Saint-Germain-en-Laye ou au Musée de l'Homme à Paris, afin d'apporter, chacun selon ses compétences, les données musicales, acoustiques et organologiques relatives à l'instrument. Suite à la disparition de Dominique Buisson, nous souhaitons communiquer les informations qu'il avait à coeur de faire découvrir à la communauté scientifique dans une prochaine publication. Que les spécialistes veuillent bien excuser nos lacunes dans le domaine de l'archéologie préhistorique. Dominique Buisson aurait sû, bien plus adroitement que nous, parler de cette flûte à laquelle il avait rendu la "voix" en travaillant, muni de silex taillés, un os de vautour.

cote interne IRCAM: Verge95a; /; National audience; In this paper, a simple one-dimensional representation of recorder-like instruments for sound synthesis by physical modeling is presented. The jet oscillation model used is a modification of the semi-empirical model by Fletcher (1976b). The steady-state of the acoustical oscillations in the pipe by the jet motion is represented by a pressure jump in the mouth of the instrument. Vortex shedding at the edge of the labium during steady-state operation is taken into account by the use of a free jet model. The combined effects of this non-linearity and the jet-drive model enable one to predict correctly the steady-state amplitude of the fundamental. The transient response of the model is triggered by the initial volume injection into the mouth of the instrument and is dependent on the steepness of the driving pressure rise.

cote interne IRCAM: Derogis95a; /; National audience; In all string instruments, the sound is radiated as a result of the coupling of the strings with a plate. In the case of the piano the energy given by the hammer to the string, flows through the bridge to the soundboard which dissipates it into internal losses and sound power. Thus the soundboard acts like a mecano-acoustic transducer. In this study a modal analysis is used in order to investigate the vibration characteristics of an upright piano soundboard. The results of this analysis are used for computing the radiation characteristics of the soundboard. Finally a way to improve the radiation efficiency of the soundboard in the low frequencies is proposed.

cote interne IRCAM: Causse93a; None / None; National audience; En trois siècles bientôt d'existence, le piano n'a cessé d'occuper une part toujours plus ample de la scène musicale. De multiples améliorations techniques en ont fait cet instrument complet et fiable que nous connaissons tous. Malgré sa perfection, l'instrument semble n'avoir jamais posé autant de problèmes aux compositeurs qu'aujourd'hui. L'avenir serait-il à la synthèse ?

cote interne IRCAM: Weinreich91a; /; National audience; Using the approach first pioneered by Raman, the Helmholtz motion of a bowedstring is discussed as a special case of "two-velocity motions," in which a givenpoint (at which the bow is located ) alternates, in the course of a cycle, betweentwo constant velocities. The fact that the bow typically presents a negativeresistance to the string during the "slipping" part of the cycle is adduced as areason for the "duty cycle," that is, the fraction of the period that corresponds toslipping, to try to become as short as possible. It is shown that, for a stringwithout dissipation or stiffness, this duty cycle can be arbitrarily low for generalbow positions; data obtained with the "digital bow" illustrate this behavior. It isshown theoretically, and confirmed with computer simulations, that instabilitiesarising from the negative slipping resistance cannot be eliminated by assigning afinite positive value to the sticking resistance. The apparent stability of Helmholtzmotion observed in real playing situations remains a puzzle.

cote interne IRCAM: Maganza86a; /; National audience; Wind instrument provide interesting hydrodynamical systems where non-linearities are importantbut well localized. A simple analysis shows that these systems should undergo Feigenbaum-typeroute to chaos, with a cascade of period doublings. Experiments have been performed with anacoustical resonator and an "artificial" excitation (nonlinearities controlled by either analogic ordigital devices); they have confirmed these predictions.