EXPERIMENTAL CHARACTERISATIONS OF SINGLE CANE REEDS

International audienceSingle cane reeds used for playing clarinets or saxophones are described by makers by their strength and shapes (cutting). For reeds assumed to be identical according to the maker (same strength and shape), strong differences in the perceived quality are expressed by musicians. In this context, the experimental characterization of reeds (from the perceptive and objective sides) is a key issue for reed makers in order to better predict reed musical abilities. This paper presents and discuss different measurement methods. These methods can be divided into two families, measurement of the reed alone through static or dynamic measurements in order to derive stiffness and modal parameters, measurement of the "embouchure" (reed+mouthpiece+lip) alone through static or quasi-static measurements in order to estimate the non linear characteristics, the non linear reed stiffness or other mechanical parameters. Finally it appears that the most efficient characterisation of the "embouchure" is probably a static measurement

Analysis of Nonlinear Characteristics of the Clarinet Exciter Obtained via a New Measurement Method

International audienceA new method for measuring the nonlinear characteristic of the clarinet exciter, which binds the air flow entering into the clarinet with the pressure drop (∆p) across the reed, is described. It uses a clarinet mouthpiece equipped with a reed and an artificial lip whose position ψ is controlled by a micrometer screw. The mouthpiece is connected to a bottle in which a moderate vacuum is generated at the beginning of the experiment. After a short time lapse, the opening of the reed occurs. The ther-modynamics of the volume in isochoric conditions enables the calculation of the volume velocity entering the mouthpiece from the pressure measurement. 13 reeds with 10 different embouchures are measured. The measurements enabled the estimation of the equivalent aeraulic section S(∆p, ψ). We propose a model of S as a convex function of ∆p and ψ, defined as the sum of two 1D stiffening springs plus a porosity constant. The mean standard error of the model is 0.2%

WHAT WE UNDERSTAND TODAY ON FORMANTS IN SAXOPHONE SOUNDS?

International audienceThe question of the formants in saxophone sounds involves several paradoxes. The analogy with "cylindrical saxophones", i.e. cylindrical tubes excited at a given proportion of the length, is classical and can be extended to the bowed string. This analogy leads to an approximation of the spectrum of the pressure inside the mouthpiece valid only at low frequencies. Nevertheless it gives good results even at higher frequency, this paradox being now understood. The spectrum of the external pressure contains formants which are different from that of the internal spectrum. The question of what is the cause of the formants remains open

Role of the Resonator Geometry on the Pressure Spectrum of Reed Conical Instruments

International audienc

La délivrance du Subutex® (un nouveau défi)

CAEN-BU Médecine pharmacie (141182102) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF

Scaling of reed instruments : the case of the saxophone family

The saxophone family is one of the most extended musical instruments family from the contrabass to the sopranino. The timbre of these instruments is unmistakable: there is a small probability to mix up a saxophone with an oboe or a bassoon. Now a question is: What is so specific in the timbre of the saxophones? Notes of various saxophones are recorded, analyzed, and compared with those of other instruments such as the oboe. More specifically, the transient duration and the formant frequency are determined. Then, the question which physical parameters influence the transient duration and the formants is studied. The influence of geometrical parameters such as the cone angle and the length of the cone truncation will be discussed

Link between objective and subjective characterizations of Bb clarinet reeds

International audienceThis paper deals with the subjective and mechanical characterizations of single cane reeds. Subjective tests performed by a single expert gave an estimation of the subjective descriptors “ease of playing”, “brightness”, “roundness”, “projection” and “global quality”. The mechanical characterization involved measurements of static compliance, dynamic compliance, resonance frequency and Q factor of the first vibration mode. Two sets of clarinet reeds were studied. The first set contained 50 reeds identical in cut, brand and strength. The second set contained 150 reeds with 3 different cuts but identical in brand, strength and static compliance. Results show that the perceptual space is almost bi-dimensional for the first set of reeds and mono-dimensional for the second set. For the first set, the two dimensions were largely created by the descriptors ease of playing (highly correlated to brightness) and roundness. For the second set (with a constant static compliance), the main dimension was created by all the descriptors, that are correlated. The study of correlation coefficients between subjective descriptors and mechanical parameters shows that the static and dynamic compliance are correlated with the descriptor ease of playing for set 1. For set 2, the correlations are too low to make a link between the perceptual space and the objective parameters

Recherche d’indicateurs de qualité d’anches simples – partie 2 : approche subjective

International audienc

Recherche d’indicateurs de qualité d’anches simples – partie 1 : estimation des paramètres équivalents en régimes statique et quasi-statique

International audienceL’anche simple utilisée sur les clarinettes ou saxophones reste une partie de l’instrument encore mal connue aujourd’hui. De façon à tenter de comprendre la variabilité des anches perçue (par les musiciens), un musicien artificiel en dépression (MAD) est utilisé pour estimer les paramètres équivalents à l’anche en régimes statique et quasi-statique. Ce dispositif permet la mesure de la force d’appui de la lèvre sur l’anche, la mesure de la pression dans le bec et l’estimation du débit entrant dans l’instrument lorsque l’anche s’ouvre lentement (quelques secondes). Ces mesures conduisent à l’estimation de la raideur mécanique et à celle de la section d’ouverture de l’anche en fonction de la pression généralisée (définie grâce à l’aire équivalente à l’anche). La description de la section d’ouverture à l’aide d’un modèle équivalent permet de définir 4 paramètres. Au final, l’ensemble de ces mesures donne accès à 6 paramètres physiques équivalents à l’anche. Un ensemble d’anches joué par un musicien (humain) à plusieurs reprises (anches neuves, rodées, jouées 1 puis 2 fois) est caractérisé à l’aide du MAD et une analyse de la variance a été effectuée sur les paramètres équivalents. Les résultats montrent que trois paramètres présentent des effets significatifs pour expliquer le vieillissement de l’anche

Role of the Resonator Geometry on the Pressure Spectrum of Reed Conical Instruments

International audienceSpectra of musical instruments exhibit formants or anti-formants which are important characteristics of the sounds produced. In the present paper, it is shown that anti-formants exist in the spectrum of the mouthpiece pressure of saxophones. Their frequencies are not far but slightly higher than the natural frequencies of the truncated part of the cone. To determine these frequencies, a first step is the numerical determination of the playing frequency by using a simple oscillation model. An analytical analysis exhibits the role of the inharmonicity due to the cone truncation and the mouthpiece. A second step is the study of the input impedance values at the harmonics of the playing frequency. As a result, the consideration of the playing frequency for each note explains why the anti-formants are wider than those resulting from a Helmholtz motion observed for a bowed string. Finally numerical results for the mouthpiece spectrum are compared to experiments for three saxophones (soprano, alto and baritone). It is shown that when scaled by the length of the missing cone, the anti-formant frequencies in the mouthpiece are very similar for the three instruments. The frequencies given by the model are close to the natural frequencies of the missing cone length, but slightly higher. Finally, the numerical computation shows that anti-formants and formants might be found in the radiated pressure