Physical modelling of the string/finger interaction in the acoustic guitar

• Grant number: 22/07224-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): November 01, 2022
• Effective date (End): October 31, 2023
• Field of knowledge: Linguistics, Literature and Arts - Arts - Music
• Principal Investigator: Marcelo Gomes de Queiroz
• Grantee: Guilherme Orelli Paiva
• Supervisor: Jean-Loïc Le Carrou
• Host Institution: Instituto de Matemática e Estatística (IME). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: Université Paris-Sorbonne (Paris 4), France
• Associated to the scholarship: 20/07978-0 - Psychoacoustical studies based on full physical modelling for acoustic guitars sound synthesis, BP.PD

Abstract

The present research plan is part of the post-doctoral work in progress whose title is "Psychoacoustical studies based on full physical modelling for acoustic guitars sound synthesis". Such work addresses the development of an acoustic guitar sound synthesis model whose framework is based on the coupling of four individual subsystems describing the plucking mechanisms, the strings, the instrument body and the sound radiation. The main research effort is to investigate, through systematic simulations and psychoacoutical studies, the influence of the physical-mechanical parameters of the guitar body materials (woods) on the sound. Based on that, the plucking model has been severely simplied so that many influential aspects provoked by the guitarist's plucking action have been neglected. During performance, every guitarist is able to vary specific parameters of the plucking action in order to obtain a desirable sound quality. These are (i) the plucking position, (ii) the angle with which the string is attacked, (iii) the angle with which the string is released, (iv) the way of touching the string before the attack (in practice, nail, flesh, or both) and (v) the initial displacement of the string, resulting from the plucking force. Therefore, the present research plan aims at developing and including to the current synthesis framework a realistic physical model capable of describing the string/finger interaction during the guitar plucking. For this purpose, a set of thorough experimental studies will be performed using a high-speed camera to film the string/finger interaction during various plucks, which will allow to estimate the model parameters and their variabilities. In addition, it is also intended to perform non-intrusive indirect measurements from various plucks so that the instrumentalist will be able to play the acoustic guitar as naturally as possible. In this case, in order to estimate the model parameters, an optimization method will proposed to solve the posed inverse problem. Furthermore, a set of systematic parametric simulations will be carried out in order to study the influence of each plucking parameter on the guitar sound. Finally, the variability effects of the wood physical-mechanical parameters in comparison to the plucking parameters ones will be investigated by using a stochastic approach for the guitar sound synthesis. (AU)