Evaluation of Araucaria angustifolia (Bertol.) Kuntze wood for acoustic guitar production and musical acceptance of the instrument

Abstract

Background:
The acoustic quality of a guitar is directly influenced by the wood species used in its construction. Brazil has a diverse range of tree species with potential for lutherie, which could reduce production costs and encourage sustainable cultivation. In this context, this study evaluated the suitability of Araucaria angustifolia, a native species from southern Brazil, for use in guitar manufacturing. Acoustic, anatomical, chemical, physical, and mechanical properties of wood samples from three trees were analyzed, followed by the construction and evaluation of a guitar prototype.

Results:
The results demonstrated promising acoustic performance, with a sound velocity of 4657 m·s⁻¹, a fundamental frequency of 199.1 Hz, and a logarithmic decay of 0.019 s. The wood showed suitability for use in the soundboard and back of the guitar. Significant correlations were observed between acoustic and mechanical properties and anatomical and chemical characteristics, including bordered pit diameter, solubility in ethanol and water, basic density, and tangential hardness. The wood exhibited a density of 430 kg·m⁻³ and lower shrinkage values compared with conventional tonewoods. Mechanical behavior was consistent with low-density woods, with an elastic modulus of 10,469 MPa. Evaluations conducted by professional musicians classified the instrument’s tonal quality as “Good” or “Very Good”.

Conclusion:
The findings indicate that Araucaria angustifolia has significant potential for guitar manufacturing, especially in applications requiring lightweight tonewoods with favorable acoustic performance. The species represents a promising alternative for lutherie, contributing to the diversification of raw materials and the valorization of native Brazilian woods.