Papers by Adrien Mamou-Mani
Journal of Sound and Vibration, 2015
In recent years, there has been a growing interest in smart structures, particularly in the field... more In recent years, there has been a growing interest in smart structures, particularly in the field of musical acoustics. Control methods, initially developed to reduce vibration and damage, can be a good way to shift modal parameters of a structure in order to modify its dynamic response. This study focuses on smart musical instruments and aims to modify their radiated sound. This is achieved by controlling the modal parameters of the soundboard of a simplified string instrument. A method combining a pole placement algorithm and a time-dimensionless state-derivative control is used and quickly compared to a usual state control method. Then the effect of the mode tuning on the coupling between the string and the soundboard is experimentally studied. Controlling two vibration modes of the soundboard, its acoustic response and the damping of the third partial of the sound are modified. Finally these effects are listened in the radiated sound.
International Computer Music Conference, 2015
This article discusses progress and advances in the Acoustic-Aggregate-Synthesis project (first d... more This article discusses progress and advances in the Acoustic-Aggregate-Synthesis project (first described in Proceedings from ICMC, 2012). Acoustic-Aggregate-Synthesis is a real-time performancetool which fuses synthetic and acoustic sound sources in order to achieve semi-acoustic re-synthesis of a pre-defined acoustic model. This technology functions most effectively, from a cognitive stand-point, when it is used with an instrument which has been modified in order to allow synthesis to emanate via the same channels as those from which that instrument's acoustic signal emanates (i.e. with electronic diffusion of synthesis taking place inside the instrument itself). Thus, the project comprises elements of both software development and instrument modification. At the heart of this initiative is the desire to maintain the acoustic amplification & diffusion patterns, attack/sustain/release characteristics, etc. of a given instrument whilst overriding its timbral characteristics in favour of a contrasting, secondary tone.
Proceedings of Meetings on Acoustics, 2013
In the following study, the state derivative control is used to complete the usual state control.... more In the following study, the state derivative control is used to complete the usual state control. This combined method allows the control of the vibration amplitude of a structure while ensuring the stability of the feedback loop. Firstly, this article presents the approach which leads to development of a combined control method. Then, simulations are presented in trivial examples to illustrate this method. Finally, an application on simulated simplified soundboard is tested and advantages and difficulties linked to the use of this method on an experimental case are shown.
Adjusting the soundboard’s modal parameters without mechanical change: A modal active control approach
Journal of the Acoustical Society of America, Oct 1, 2014
How do modes of soundboards affect the playability and the sound of string instruments? This talk... more How do modes of soundboards affect the playability and the sound of string instruments? This talk will investigate this question experimentally, using modal active control. After identifying modal parameters of a structure, modal active control allows the adjustments of modal frequency and damping thanks to a feedback loop, without any mechanical changes. The potential of this approach for musical acoustics research will be presented for three different instruments: a simplified piano, a guitar, and a cello. The effects of modal active control of soundboards will be illustrated on attack, amplitude of sound partials, sound duration, playability, and “wolf tone” production.
Journal of Vibration and Control, Aug 23, 2017
Modal active control is based on a state model that requires the identification of modal paramete... more Modal active control is based on a state model that requires the identification of modal parameters. This identification can typically be done through a rational fraction polynomial algorithm applied in the frequency domain. This method generates numerical problems when estimating high-order models, particularly when moving from the basis of orthogonal polynomials for the modal basis. This algorithm must therefore be applied independently on multiple frequency ranges with a low order for each range. In this case, the controller design cannot be automated and requires a lot of human intervention especially to build the state space model. To address this issue, this paper presents the application of the direct modal parameters estimation algorithm for active modal control design. The identification algorithm is presented in a simplified version with only positive frequencies. Unlike other classical identification methods in the frequency domain, the direct modal parameters estimation algorithm provides a solution with a great numerical stability and allows estimating models with a higher order. Using this method, the design of the controller can be largely automated and requires a minimal of human intervention. After a theoretical presentation, the proposed method is experimentally validated by controlling the vibration modes of a suspended plate.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 23, 2012
This study aims to control the soundboard's vibrational modes in order to modify the timbre of st... more This study aims to control the soundboard's vibrational modes in order to modify the timbre of string instruments. These structures are wooden plates of complex shapes, excited by strings through a bridge. In order to apply an efficient control on such systems, modal parameters must be identified using classic algorithms applied on experimental measurements. Then it is possible to design a feedback controller using these parameters and classic control methods. At first, a simulation of the control has been done for a rectangular spruce plate, boundary clamped and excited by a single string. This simplified case and first results in term of changes in eigenmodes are presented here.
Simulated Effects of Combined Control of an Experimentally Identified Soundboard
HAL (Le Centre pour la Communication Scientifique Directe), 2013
ABSTRACT cote interne IRCAM: Benacchio13a
HAL (Le Centre pour la Communication Scientifique Directe), 2015
This study proposes an application of modal active control on musical string instruments. Its aim... more This study proposes an application of modal active control on musical string instruments. Its aim is to control the modal parameters of the soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure's characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied on a model of a simplified string instrument soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
Investigating the consistency and quality of musical wind instrument manufacturing
ABSTRACT For large-scale musical wind instrument manufacturers, the ability to produce instrument... more ABSTRACT For large-scale musical wind instrument manufacturers, the ability to produce instruments in a repeatable fashion is essential. However, despite the tight manufacturing tolerances used, professional musicians are often able to discern small, but perceptible, differences between the playing characteristics of instruments manufactured in an identical way. These differences are most likely a result of tiny disparities in bore profile or in the positioning/sealing of any side holes. This talk outlines a programme of work designed to investigate the consistency with which manufacturers are able to make wind instruments and to explore the causes of any musical differences between the instruments. State-of-the-art techniques will be used to measure the internal geometries and resonance characteristics of batches of nominally identical instruments. Meanwhile, the musical qualities of the instruments will be established through a series of psychoacoustical tests. The potential effectiveness of the proposed approach will be demonstrated through a set of measurements made on two low-cost, mass-manufactured trumpets.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 23, 2012
For large-scale musical wind instrument manufacturers, the ability to produce instruments in a re... more For large-scale musical wind instrument manufacturers, the ability to produce instruments in a repeatable fashion is essential. In this paper, two mass-produced trumpets of the same model type are compared in terms of physical and perceptual differences. Input impedance and bore profile measurements show significant acoustical differences due to the presence of a tiny leak in the bore of one of the two instruments. Psychophysical tests demonstrate that these acoustical differences do not necessarily result in perceptible differences in the playing characteristics of the two trumpets. Only a small number of trumpet players successfully distinguish between the instruments when subjected to a playing test, although those that do are shown to be able to provide distinct and consistent quality assessments for each one.
Journal of the Acoustical Society of America, Mar 1, 2016
The vibrational behavior of musical instruments is usually studied using physical modeling and si... more The vibrational behavior of musical instruments is usually studied using physical modeling and simulations. Recently, active control has proven its efficiency to experimentally modify the dynamical behavior of musical instruments. This approach could also be used as an experimental tool to systematically study fine physical phenomena. This paper proposes to use modal active control as an alternative to sound simulation in order to study the complex case of the coupling between classical guitar strings and soundboard. A comparison between modal active control and sound simulation investigates the advantages, the drawbacks and the limits of these two approaches.
Modal proportional and derivative state active control applied to a simplified string instrument
Journal of Vibration and Control, Aug 9, 2016
This study proposes an application of modal active control to musical string instruments. Its aim... more This study proposes an application of modal active control to musical string instruments. Its aim is to control the modal parameters of the soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure’s characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied to a model of a simplified string instrument soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
Acta Acustica United With Acustica, Sep 1, 2011
Capillary-based systems for measuring the input impedance of musical wind instruments were first ... more Capillary-based systems for measuring the input impedance of musical wind instruments were first developed in the mid-20th century and remain in widespread use today. In this paper, the basic principles and assumptions underpinning the design of such systems are examined. Inexpensive modifications to a capillary-based impedance measurement set-up made possible due to advances in computing and data acquisition technology are discussed. The modified set-up is able to measure both impedance magnitude and impedance phase even though it only contains one microphone. In addition, a method of calibration is described that results in a significant improvement in accuracy when measuring high impedance objects on the modified capillary-based system. The method involves carrying out calibration measurements on two different objects whose impedances are well-known theoretically. The benefits of performing two calibration measurements (as opposed to the one calibration measurement that has been traditionally used) are demonstrated experimentally through input impedance measurements on two test objects and a Boosey and Hawkes oboe.
Applied Acoustics, Jul 1, 2010
. Evaluating the suitability of acoustical measurement techniques and psychophysical testing for ... more . Evaluating the suitability of acoustical measurement techniques and psychophysical testing for studying the consistency of musical wind instrument manufacturing. Applied Acoustics, 71(7) pp. 668-674. For guidance on citations see FAQs.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 11, 2022
Les actionneurs inertiels électrodynamiques sont des systèmes compacts permettant d'exciter les s... more Les actionneurs inertiels électrodynamiques sont des systèmes compacts permettant d'exciter les surfaces sur lesquelles ils sont fixés. Ils peuvent être utilisés pour de la diffusion sonore ou du contrôle actif de vibration. Par exemple, ils peuvent être combinés à un capteur vibratoire colocalisé afin d'ajouter de l'amortissement à une surface. Cependant, l'ajout d'un capteur vibratoire est coûteux et la colocalisation avec l'actionneur peut être impossible pour des raisons d'encombrement. Cette communication présente l'utilisation d'actionneurs inertiels en mode capteur/actionneur afin de s'affranchir du besoin d'un capteur externe. Le capteur/actionneur est piloté en tension et le courant est mesuré à l'aide d'une résistance de shunt. La combinaison de la tension et du courant permet de mesurer la force contre-électromotrice, proportionnelle à la dérivée de l'élongation de la suspension de l'actionneur. Cette grandeur est contrôlée dans une boucle de rétroaction. Nous présentons des simulations de contrôle sur des surfaces de différentes mobilités ainsi que des résultats expérimentaux sur une plaque fine encastrée en aluminium.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 11, 2022
Afin de palier aux problèmes d'encombrement et de poids des haut-parleurs conventionnels, de nomb... more Afin de palier aux problèmes d'encombrement et de poids des haut-parleurs conventionnels, de nombreux travaux s'intéressent aujourd'hui au rayonnement de structures vibrantes munis d'actionneurs inertiels pour diffuser du son. Les Haut-Parleurs à Panneau Plat (Flat-Panel Speaker) en particulier consistent en une plaque équipée d'un actionneur électro-dynamique afin de rayonner du son par l'intermédiaire d'ondes de flexion. Cependant, les résonances vibratoires de la plaque ont un effet négatif sur la qualité perçue du rayonnement, notamment aux basses fréquences et pour des structures faiblement amorties. Par ailleurs, le contrôle vibratoire actif permet d'amortir efficacement ces résonances vibratoires. L'objectif des travaux présentés est d'étudier l'efficacité du contrôle vibratoire actif pour optimiser le rayonnement des Haut-Parleur à Panneau Plat dans la bande de fréquence de 80Hz à 1000Hz. Dans ce but, nous avons construit un prototype constitué d'une plaque d'aluminium rectangulaire, de dimension 28.5cm x 43cm x 1.5mm, encastrée et excitée par un actionneur. Des expériences en chambre anéchoïque ont été menées pour en mesurer le rayonnement dans plusieurs configurations de contrôle vibratoire actif et pour deux positions de l'actionneur. La première favorise l'excitation des modes symétriques (cas 1), la seconde permet l'excitation de tous les modes (cas 2). Ces mesures montrent que dans le cas 1, le contrôle actif améliore la réponse acoustique, résultant en un rayonnement plus homogène selon les fréquences. En revanche dans le cas 2, on ne peut pas conclure que le contrôle améliore le rayonnement. Ces résultats sont corroborés par un modèle numérique du système faisant appel à la méthode des éléments de frontière.
Une sourdine sèche active pour le trombone
HAL (Le Centre pour la Communication Scientifique Directe), Apr 23, 2018
Active control is widely used in industry. However, there have been relatively few applications t... more 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.
This study proposes an application of modal active control on musical string instruments. Its aim... more This study proposes an application of modal active control on musical string instruments. Its aim is to control the modal parameters of the soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure’s characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied on a model of a simplified string instrument soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.
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Papers by Adrien Mamou-Mani