Evaluating urban oriental plane wood as a tonewood: effects of solvent extraction on acoustic performance

This research investigates the acoustic potential of mature Oriental plane wood (Platanus orientalis L.) harvested from urban environments for use in musical instrument manufacturing. While traditionally undervalued as low grade raw material, this species offers unique aesthetic properties that could be enhanced for high value lutherie applications. The study aimed to determine if solvent extraction could improve the wood's acoustic properties to meet standard criteria for instrument soundboxes. Forty clear, straight grained radial specimens were prepared and subjected to sequential extraction using pure water and a 1:3 acetone-ethanol solution via a Soxhlet system. Dynamic mechanical properties were evaluated using a non-contact forced vibration system. Results indicated that while solvent washing consistently reduced air-dry density and the longitudinal modulus of elasticity, the acoustic radiation coefficient remained stable or slightly increased, particularly with the ethanol-acetone treatment. However, extraction significantly increased the damping capacity, suggesting that the removed extractives, much like those in Pernambuco wood (Caesalpinia echinata Lam.), play a structural reinforcement role within the cell wall. While plane wood requires careful impedance matching for use in resonance boxes, its extractives present a promising opportunity for impregnating other species to enhance their acoustic performance.