Vibration analysis of top plates of acoustic guitars

Abstract

The present work raises from the vibratory experimentation with two top plates of guitars of different characteristics as for quality and origin of materials, with a traditional Torres bracing, at free edge conditions, disconnected of the guitar's body. By employing the Chladni's Traditional Method, the most important vibrational modes are visualized and located. Furthermore, the measurement of vibratory amplitude is analyzed through the utilization of suitable instruments, in order to observe the quantitative effects of the material variability conditions and the bracing influence that every harmonic plate possesses. The development of this experience allows the identification of vibrational modes and sound radiation patterns in free vibrational conditions. The method consists on the solely isolation of the analysis for vibratory behavior to the harmonic plate. In this way, an overall knowledge of its behavior with respect to bars adhesion (mass) and its arrangement can be acquired. However, the subsequent effect of processes such as coupling or varnished, among others, are not considered.