An experimental modal analysis on the coimbra model of the Portuguese guitar

Abstract

The most distinctive Portuguese traditional music style is Fado. In this form of Portuguese music, a singer is accompanied by two instruments: a classical guitar and a pear shaped plucked chordophone with six courses of double strings—the Portuguese guitar. There are two distinct types of this instrument—the Lisbon and the Coimbra models—named after the towns where the two different styles of Fado have developed. These guitars differ basically on their size and tuning, both comprising 6 orders of double steel strings, while the construction method (strutting patterns, wood species used, and soundboard thickness distribution) vary for different builders. As part of an ongoing research project that investigates the vibroacoustical behavior of this instrument for different types of designs, an experimental modal analysis of a fully assembled Coimbra guitar was performed. In this work, we present the results of this analysis showing the main characteristics of the frequency response curves and significant vibratory modes as compared to other similar plucked-string instruments.