The effects of a musician’s body on back plate vibrations of acoustic guitars

Back plate vibrations of acoustic guitars are of interest to luthiers and researchers. However, during many playing situations, the back plate of the guitar is damped by the musician’s body. This body damping is particularly common with steel-string acoustic guitars as they are typically held close to the body when played sitting, or rest against the body when played standing. While most measurements and simulations of acoustic guitars assume free mounting conditions and ignore any effects of the musician’s body on the instrument, this study investigates the additional player-induced back plate damping. Vibration and acoustic measurements in free and damped conditions of multiple steel-string acoustic guitars of varying geometries and materials are presented. Auralizations are used to compare the sonic differences between the free and damped back plate cases for each guitar.