Modal analysis of different types of classical guitar bodies

Resonant frequencies and Chladni patterns of different types of classical guitar bodies were investigated to continue and further develop the understanding of the tonal qualities of guitars. The acoustic boxes with four types of strutting systems were analyzed. For this, a B&K mini-shaker, to excite the structures, and three B&K 4517-002 accelerometers located on top, at the back and on the sides of the sound box were used. The input and output signals were collected with a Data Acquisition device (DAQ) and processed to discover resonant frequencies and harmonics. During the experiments, Chladni patterns were obtained using powder sand on the surface. The method used does provide some insight regarding the vibrations of classical guitar bodies such as the influence of the strutting system on the modal shapes and dynamic response. The paper carries on the theoretical studies presented in works [4], [5], [6], [14], [15], [16], with experimental research.