Towards model-based approaches for musical instruments making: validation of the model of a Spanish guitar soundboard and characterization features proposal

Abstract

Nowadays, the virtual prototyping method is widely used for industrial applications and can lead to a powerful tool for musical instruments making and conservation. Nevertheless, physics-based models of musical instruments are barely developed for this purpose and the confrontation between model predictions and experiments have been the focus of very few researches. The objective of this paper is to highlight the predictive capability of physics-based models in dynamic domain, even in presence of variable by nature material and climatic conditions. For this purpose, a finite element model of the soundboard of a Spanish guitar is developed for model validation purposes. The simulated modal bases are compared with experimental ones from a previous study. Screening and stochastic analyses are performed to rank which are, among material and climatic parameters, the most influential ones on the dynamics of guitar soundboard. Moreover, uncertainties are taken into account to evaluate the dispersion of the response for a given design, and simulations are validated facing experimental data. It is shown that specific elastic parameters of the wood (in longitudinal and radial directions and longitudinal-radial plane) of the top plate are mainly

A Review of Finite Element Studies in String Musical Instruments

“…A simplified FE model of the soundboard by Moore and Zietlow [67], along with ESPI experimental measurements, demonstrated that the vertical force exerted by Recently, Salvi et al [63] analyzed the modal response of the free top plates of archtop guitars via FEM and investigated the similarities of its mode shapes with those of similar instruments, such as the violin and the classical guitar. Moreover, Viala et al [64] demonstrated, via numerical and experimental modal analysis and uncertainty quantification, that the specific elastic parameters of the wood (in longitudinal and radial directions and longitudinal-radial plane) mainly influence the dynamics of the soundboard, whilst the relative humidity changes have a non-negligible impact.…”

Model-based evidence of the dominance of the guitar brace design over material and climatic variability for dynamic behaviors

“…For each eigenmode, the deformed shapes are displayed and the bridge admittance is computed with the modal superposition method. A modal damping ratio based on the experimental values is used (ξ = 1.15%) [22] for the bridge admittance calculation. In this study, a stochastic analysis is performed based on the probabilistic definition of the material parameters.…”

“…where ∆N m represents the number of modes that exist in a specific bandwidth ∆f , the bandwidths is defined as third octave band here. η is the loss factor of the system in the bandwidth and is considered here equal to 2.3 %, which is twice the modal damping value measured on guitar soundboards in [22], [10].…”

“…In addition to the computation of the modal basis of guitar soundboards, the models have been used to compute the bridge admittance of the guitar [20]. Another feature, the complex frequency domain assurance criterion has been used to evaluate the impact of a non-invasive restoration [21] and validate a model [22].…”

Use and sustainability of wood in acoustic guitars: An overview based on the global market

“…Since acoustic properties are determined by physic-mechanical characteristics, several studies focus on exploring indices and parameters (e.g. density and Young's modulus) that influence the acoustic response of wood by determining the speed and intensity of the sound [ [9] , [10] , [11] , [12] , [13] ].…”