The paper presents different study methods on stringed musical instruments, providing case studies for each of the methods for evaluating the quality of musical instruments. Thus, the article approaches five ways of evaluating violins, starting from the quality of the raw material, the wood, to the technological process that combines modern wood processing techniques with traditional techniques, to the imaging analysis of old and modern instruments by non-invasive means, to the modal analysis and the acoustics of violins. The multiscale approach to musical instruments is necessary to explain all the factors that contribute to the acoustic quality of the musical instrument, the laborious research being developed over several years, in different research projects in collaboration with the musical instrument manufacturers.