Violin making " tonewood " : comparing makers' empirical expertise with wood structural/visual and acoustical properties

Cette publication a fait l'objet d'un poster lors de la conférence.International audienceThe " resonance woods " for the making of violin family have benefited from more research than other instrument making woods, but the interactions between different disciplines and viewpoints in this field has seldom been addressed. The objective of this study is to improve the understanding of the interactions between physic-mechanical properties of resonance wood, their natural variability, and the actual expertise of violin makers in the selection and qualification of their raw material. An in-depth " socio-technical " survey has been designed to identify violin makers' opinions and practices on both qualitative and quantitative grounds. In parallel, tonewood samples of various " qualities " were characterized for their physical and vibrational properties (density, anisotropic specific moduli and damping coefficients), acoustical " performance indexes " , and visual/structural characteristics (growth-ring uniformity and percentage of latewood). Correlations between visible structural characteristics, density and vibrational properties in spruce " resonance wood " were not typical of classical softwoods and highlight the peculiarity of this pre-selected material, which can be discussed through microstructural explanations. Empirical choice by violin makers, based on perceptual criteria that can be visual, physic-mechanical, auditory, are relevant to the acoustic properties measured but will require a more detailed study to evaluate the respective contribution of these different fields of perception. We also intend to construct a model to evaluate the properties of a full violin plate from sampling fabrication offcuts