Contemporary interest in full waveform inversion (FWI) drives development of 3D forward modeling algorithms. Performing FWI in the frequency domain effectively reduces an inverse problem to the series of monochromatic forward simulations. Still, forward modeling consumes bulk of the FWI run time. In this paper, we focus on efficient solution of the acoustic-wave equation. The most time-consuming step in numerical solution of the acoustic-wave equation is iterative solution of the arising system of linear equations. A slow convergence of iterative solvers is related to the spectral properties of the system matrix [Ernst and Gander, 2012]. Consequently, various preconditioning techniques were applied to this kind of problems.