Experiments on the dynamic stabilization of the Rayleigh‐Taylor instability are described, where the applied oscillations are modulated in their frequency or chosen to be strongly anharmonic. While, compared to the application of harmonic oscillations, an expected rise of the excitation threshold of parametric instabilities could be observed, a corresponding shift of the boundary discriminating against the slowest Rayleigh‐Taylor mode did not allow to obtain a measurable increase of the over‐all stability region.