A theoretical model of the acoustic effect of crystallization is suggested based on the representation of a stepwise character of formation or disappearance of macrolayers and macroregions on a growing (or melting) surface. According to this model, the picture of oscillations reproduces in basic features the form of the signals observed in experiments. The oscillation frequency of the liquid is determined by the frequency of generation of jumps at the crystallization front, while the comparatively large values of peak pressures in acoustic waves are a consequence of the resonance phenomena.