Fermentation pretreatment and extraction’s effect on the acoustic properties of walnut wood (Juglans regia)

Abstract

Despite the progress in synthetic polymer industries, wood is one of the main materials in making musical instruments because of its unique characteristics. Many instrument makers try to improve the acoustic properties of wood by traditional treatments. In this study, the changes in the acoustic properties of walnut wood during the processes of fermentation pretreatment, water washing, and organic solvent washings were evaluated. For this, the samples were divided into two groups of 20. For the first group, de-extraction was started with fermentation pretreatment, while the second group samples directly underwent stepwise extraction, using hot water and ethanol-acetone solvents. The results showed a decrease in density, dynamic modulus of elasticity, and damping factor due to the soaking process. But the elastic stiffness did not change. The values of the acoustic coefficient and the acoustic conversion efficiency increased due to the soaking process. The values of density, dynamic modulus of elasticity, elastic stiffness, and damping factor decreased due to ethanol-acetone washing, while the acoustic coefficient and acoustic conversion efficiency showed a significant increase. In general, soaking process and ethanol-acetone washing with fermentation pretreatment improved the acoustic properties of walnut wood.