On the vibro-acoustic characterization of two similar violas da gamba

The paper summarizes the main aspects of an experimental vibro-acoustic investigation developed by the authors on two violas da gamba (named in the following as viols). The considered instruments show similar aesthetic and geometric characteristics, as one of them was made later adopting the other as a reference. However, they are characterized by non-negligible different construction solutions, such that is not possible to consider one a faithful replica of the other. The instruments considered are a 16th century viol (hereinafter referred to as ancient viol) and a 21st century viol, inspired by the ancient instrument (hereinafter referred to as the modern viol). The ancient instrument has no bass bar and no sound post and has a rounded back. The modern one was deliberately made with a flat back, to follow the Italian school of construction of this type of instrument and, during this activity, it has been available in different configurations with and without bass bar and sound post. The availability of these two viols made it possible to evaluate how different construction solutions have a significant impact on both structural and acoustic response. Experimental modal analysis and operational vibro-acoustic response techniques have been extensively adopted for this aim. Considering its high intrinsic value, the measurements on the ancient viol have been reduced to the minimum necessary to obtain the suitable identification thereof. On the contrary, broad experimental activity on the modern viol has made its development possible, in analyzing its structural modification, related to the insertion of the bass bar and sound post, in order to verify the acoustic variations resulting from these variants. The different behavior of the ancient viol, with respect to the modern one, has also been analyzed to underline how the sound itself changes from an antique to a contemporary conception of stringed musical instruments.