Numerical modeling of guitar radiation fields using boundary elements

Boundary element (BE) methods have been used to supplement an existing numerical model of the classical guitar. This model computes, from fundamental parameters, the transfer between the plucking force at a point on the string and the acoustic pressure at the listening point. Structural mode shapes are determined from finite element (FE) analysis. The computed surface velocities are then used to determine the coupling between the top plate and strings and also the coupling between the top plate and Helmholtz air resonance of the body cavity. The resultant acoustic radiation is calculated using the BE formulation, in which the entire surface of the guitar body is divided into boundary elements with surface velocities being specified over the top plate and zero elsewhere (to simulate “rigid” back and sides). The computed radiation fields will be compared with measurements on real systems. Future work will involve coupling of the FE and BE methods in order to account for fluid loading.