Modal analysis of a grand piano soundboard

This paper illustrates the results of the experimental modal analysis performed on a grand piano soundboard. Tests are carried out at the three most significant stages of the musical instrument manufacturing process: free soundboard before bridge gluing, free soundboard after bridge gluing and soundboard finally assembled on the piano structure. The soundboard is excited by means of two impact hammers with different masses, so as to cover the entire frequency range of interest (0-5kHz). The adopted frequency-domain identification algorithm has proved to be suitable for providing accurate results up to about 300Hz: examples of the identified soundboard natural modes are reported, for each one of the three test steps. A preliminary numerical-experimental comparison is presented at the end of the paper, by making reference to the eigenmodes computed through a finite element numerical model of the piano soundboard.