Dense and hard woods in musical instrument making : Comparison of mechanical properties and perceptual "quality" grading

International audienceMusical instruments are composed of parts which have different functions, and call for particular wood characteristics. Besides the lightweight "resonance wood" for soundboards, dense hardwoods appear in many parts: xylophone keys, drum barrels, woodwinds, bows, back, sides and necks of string instruments, and their fittings : bridges, tail-pieces and pegs, etc...Can the mechanical/acoustical properties of these woods be correlated to the perceptual "quality" choice made by instrument makers? The study is based on a sampling of 214 wood pieces from 60 species, classified in 3 groups : (i) tropical woods used in classical/modern making, such as ebonies and rosewoods ; (ii) European hardwoods with historical and/or traditional uses ; (iii) potential alternative woods, which might overcome current shortage in the supply of appropriate quality of preferred woods. Density and dynamic mechanical properties (modulus of elasticity and "quality factor" or damping) are measured by vibrational and ultrasonic methods, at the scale of the laboratory or of the workshop. We compare choices made by three makers, one of xylophones, one of violin accessories, and one of flutes, first between these three empirical grading, then by confronting them with measured mechanical properties. It appears that the "perceptual" selections by these three makers are different