The starting point of each computational scheme for the calculation of acoustic fields is the physical and mathematical modelling. In doing so, we will discuss the different physical phenomena in acoustics and their arising mathematical models being the different conservation equations as well as wave equations taking into account linear and non-linear as well as viscous effects. Thereby, we will motivate each mathematical model with practical applications to highlight the interdisciplinarity of acoustics based on fluid dynamics, thermodynamics and structural mechanics. In a first part, we will highlight the great achievements in the last years in applying appropriate Finite Element (FE) methods to different sets of acoustic equations (both continuous and discontinuous Galerkin FE formulations, non-conforming finite elements, error estimation, etc.). The second part will concentrate on the use of FE methods for practical computations including vibrational acoustics (electrodynamic loudspeaker), aeroacoustics (human phonation, noise of ventilators), thermo-viscous acoustics (micro-electro-mechanical loudspeaker) and room acoustics. Finally, we will provide a critical view to FE simulations (as well as other numerical simulation schemes) by showing the huge amount of data being produced and the complexity to differ between numerical effects or even simple input errors and physical effects. In doing so, we will point out the need of a detailed physical understanding of acoustic phenomena in combination with a strong knowledge of the used numerical scheme.