Computational modelling of string–body interaction for the violin family and simulation of wolf notes

Inácio, Octávio; Antunes, José; Wright, Matthew

doi:10.1016/j.jsv.2007.07.079

Cited by 24 publications

(19 citation statements)

References 17 publications

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“…4,9,10,12,13 A more common method to identify frequencies at which wolf notes may occur is to determine the input admittance (driving point mobility) of the bridge. 5,6,9,10,12,17,25 A high value of the input admittance for a certain frequency means a high "willingness to vibrate," which, in the case of the cello's body, may lead to a wolf note. The input admittances at the left and the right bridge foot are determined using a small impact hammer to excite the top plate of the cello in its normal direction close to the bridge feet.…”

Section: B Experimental Resultsmentioning

confidence: 99%

“…1,2,6,7,13,14 In acio and co-authors have developed a very accurate mathematical model of a cello and were able to extensively study and understand the interactions of string and body as well as the parameters that influence the occurrence of the wolf note such as the bow force and the bowing velocity. [15][16][17]…”

Section: Characteristics Of the Wolf Notementioning

confidence: 99%

“…4,9,10,26 In more recent works the cello has been modeled using modal approaches. 17,21 For the research presented in this paper a linear model for generating the wolf note and for developing the controller is set up. A combination of three coupled single mass oscillators, representing the string and the body at the two bridge feet, is used.…”

Section: Mathematical Wolf Note Modeling and Controller Designmentioning

confidence: 99%

See 2 more Smart Citations

An active-system approach for eliminating the wolf note on a cello

Neubauer

Tschesche

Bös

et al. 2018

The Journal of the Acoustical Society of America

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Wolf notes are generally undesirable sounds that occur in string instruments, particularly in cellos. State-of-the-art passive wolf note eliminators affect the whole cello sound and can become ineffective when environmental conditions and, therefore, the cello's structural properties change. In this paper, an approach is presented that uses smart materials to eliminate the wolf note with little effects to the cello's sound. Based on preliminary measurements, a mathematical model of the cello for generating the wolf note and for developing a wolf note elimination controller is set up. The controller consists of a wolf detection criterion that triggers a velocity feedback controller to actively induce damping into the cello's body whenever a wolf note is detected. The controller setup is experimentally validated by an implementation on a test cello. The velocity feedback to induce the active damping is implemented by means of a piezoelectric patch actuator attached to the cello's body. Both the results of the mathematical model and the results of the experimental investigation show a good performance in eliminating the wolf note on a cello.

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Section: B Experimental Resultsmentioning

confidence: 99%

Section: Characteristics Of the Wolf Notementioning

confidence: 99%

Section: Mathematical Wolf Note Modeling and Controller Designmentioning

confidence: 99%

See 1 more Smart Citation

An active-system approach for eliminating the wolf note on a cello

Neubauer

Tschesche

Bös

et al. 2018

The Journal of the Acoustical Society of America

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“…Commonly, in musical instruments resonances are usually sought to enhance the sound pressure levels obtained for different resonances, modifying the timbre and the qualitative aspects of the resulting sound. Research is particularly extensive in the chordophone family, particularly in the case of classical guitars [6][7][8][9][10][11][12], electric guitars [13,14], or the string family of instruments [15][16][17][18][19]. We also find studies linked to percussive chordophones such as the piano [20][21][22] and, though scarcer, those dedicated to membranophones [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

A Study of the Dynamic Response of Carbon Fiber Reinforced Epoxy (CFRE) Prepregs for Musical Instrument Manufacturing

2019

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Composite materials are presented in a wide variety of industrial sectors as an alternative to traditionally used materials. In recent years, a new sector has increasingly used these kinds of materials: the manufacture of musical instruments. Resonances of different elements that make up the geometries of musical instruments are commonly used with the aim of enhancing aspects of the timbre. These are sensitive to the mechanical characteristics of the material, so it is important to guarantee the properties of the composite. To do this, it is not uncommon to use pre-impregnated fibers (prepregs) which allow fine control of final volumetric fractions of the composite. Autoclaving is a high-quality process used to guarantee the desired mechanical properties in a composite, reducing porosity and avoiding delamination, but significantly raising production costs. On the contrary, manufacture without autoclaving increases competitiveness by eliminating the costs associated with autoclave production. In this paper, differences in dynamic behavior are evaluated under free conditions of different Carbon Fiber Reinforced Epoxy (CFRE) prepreg boards, processed by autoclave and out-of-autoclave. The results of the complex module are presented according to the frequency, quantifying the variations in the vibratory behavior of the material due to the change of processing.

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“…The full landscape of extra features is 31 too complicated to cover within the length constraints 32 of a single paper, and the discussion here is focussed 33 primarily on the additional linear-system features. Is-34 * jw12@cam.ac.uk sues concerning the friction model are mainly deferred 35 to future work (currently in progress), but two al- 36 ternative models for friction from the existing litera- 37 ture will be included among the cases presented here. 38 Some sample results of simulations will be shown, to 39 begin the process of assessing the relative importance 40 of the many ingredients of the model.…”

mentioning

confidence: 99%

Enhanced Wave-Based Modelling of Musical Strings. Part 2: Bowed Strings

Mansour¹,

Woodhouse²,

Scavone³

2016

Acta Acustica united with Acustica

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1 An enhanced model of a bowed string is developed, 2 incorporating several new features: realistic damping, 3 detailed coupling of body modes to both polarisations 4 of string motion, coupling to transverse and longitu-5 dinal bow-hair motion, and coupling to vibration of 6 the bow stick. The influence of these factors is then 7 explored via simulations of the Schelleng diagram, 8 to reveal trends of behaviour. The biggest influence 9 on behaviour is found to come from the choice of 10 model to describe the friction force at the bow, but 11 the other factors all produce effects that may be of 12 musical significance under certain circumstances. 13 14 PACS numbers: 43.40.Cw, 43.75.De 15 1 Introduction and historical 16 background 17In an earlier paper [1], a review was presented of 18 the physical ingredients necessary to give an accurate 19 travelling-wave model of the motion of a stretched 20 string in the linear range, for example as required to 21 synthesise the motion of a plucked string. That model 22 and classifying the possible regimes of vibration for a 75 bowed string. Raman was also the first to point out 76 the existence of a minimum bow force [5] as well as 77 the geometrical incompatibility of the ideal Helmholtz 78 motion with uniform velocity across a finite-width 79 bow during episodes of sticking [4], both of which were 80 confirmed later and are still topics of active research 81 [6]. 82 Using Raman's simplified dynamical model, Fried-83 lander [7] and Keller [8] published two independent 84 but similar studies. Their results indicated that if 85 dissipation is not taken into account, all periodic mo-86 tions are unstable, including the Helmholtz motion. 87 As explained later, [9, 10, 11] any small perturbation 88 to the Helmholtz motion produces unstable subhar-89 monic modulation of the Helmholtz motion. In re-90 ality, because of the energy losses in the system this 91 instability is usually suppressed, but under certain cir-92 cumstances these subharmonics can be heard, or seen 93 in measurements of bowed-string motion [9]. 94 The next major development in modelling bowed 95 string dynamics was introduced by Cremer and 96 Lazarus in 1968. Acknowledging the fact that sharp97 corners are unlikely to occur on any real string due to 98 dissipation and dispersion, they proposed a modifica-99 tion of the Helmholtz motion by "rounding" the trav-100 elling corner [12]. Cremer then developed a model of 101 periodic Helmholtz-like motion, which revealed that 102 when the normal force exerted by the bow on the 103 string is high the corner becomes quite sharp, but 104 as bow force is reduced, the corner becomes progres-105 sively more rounded [13, 14, 15]. Ideal Helmholtz mo-106 tion is completely independent of the player's actions, 107 except that its amplitude is determined by the bow 108 speed and position. Thus, this mechanism gave a first 109 indication of how the player can exercise some control 110 over the timbre of a steady bowed note. 111 In 1979, McIntyre and Woodhouse presented a com...

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Computational modelling of string–body interaction for the violin family and simulation of wolf notes

Cited by 24 publications

References 17 publications

An active-system approach for eliminating the wolf note on a cello

An active-system approach for eliminating the wolf note on a cello

A Study of the Dynamic Response of Carbon Fiber Reinforced Epoxy (CFRE) Prepregs for Musical Instrument Manufacturing

Enhanced Wave-Based Modelling of Musical Strings. Part 2: Bowed Strings

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