Gregory H. Canfield
Thomas D. Rossing
Phys. Dept., Northern Illinois Univ., DeKalb, IL 60115
Vibrational modes of four different hammered dulcimers were studied by means of holographic interferometry and experimental modal testing with impact excitation. Vibrational modes in the four dulcimers, by four different builders and having substantially different designs, showed some similarities but a number of differences as well. Unlike other string instruments (e.g., violin, guitar), the soundboard and back plate vibrated quite independently of each other. Nodal lines tended to occur along the bridges, in most vibrational modes. Mode frequencies are compared to those calculated for rectangular and trapezoidal plates.