Desenvolvimento de métodos experimentais para seleção de madeira para tampos de violão

Abstract

Soundboard wood is the most important material for the characterization and propagation of sound in acoustic guitars. Predominantly, this wood is selected empirically, based on the experience of the luthier. This approach to evaluating wood allows variations in the quality and performance of the instruments produced, which compromises the repeatability of the results. In this context, this study developed and evaluated experimental methods for the acoustic characterization of nine wood samples. The analyzed properties included density, modulus of elasticity, speed of sound in wood, sound radiation coefficient, and quality factor. Five types of tests were conducted: visual inspection, Chladni patterns, adapted tap-tone, impulse excitation, and Lucchi Meter. The responses obtained through the adapted tap-tone and impulse excitation tests were analyzed using MATLAB software and the ITA-Toolbox extension. As a result, it was possible to correlate traditional empirical methods with the properties obtained, highlighting the importance of visual inspection and radial cutting. Among the species analyzed, Italian Spruce showed the best performance, while Marupá showed potential as a national alternative. A chart was created to facilitate the choice of the most appropriate experimental method according to the desired use. For future studies, it is suggested to increase the number of samples, improve signal capture in the impulse excitation test to increase the quality of the acoustic response signal and perform an analysis of the uncertainty of measurement of the methods developed.