The purpose of this study is to develop an energy-efficient active-control device that can control cavity noise. A new control device using fluidic oscillator systems is tested, and its noise suppression effect is evaluated for cases when the oncoming boundary layer is either laminar or turbulent. As a result, it is demonstrated for the laminar flow case that a single fluidic device can completely suppress the peak cavity noise as well as the harmonic components. In the turbulent separating flow case, it is demonstrated that two synchronized devices are necessary to suppress the cavity noise.