This disclosure provides an agitator system that includes an agitator assembly of concentric power-sections, (one power-section inside another power-section both of which comprise stators and rotors). The agitator system includes a controller configured to control a valve assembly of the agitator assembly to selectively open and close the valve assembly to allow fluid to selectively flow between the power-sections of the agitator assembly that generates pressure fluctuations or pressure pluses in the fluid pressure, which increases the speed of the rotor or rotors, and thus, the vibrational frequency of the agitator. The controller can be used to increase the vibrational frequency of the agitator assembly when necessary to prevent the drill string from becoming lodged in a wellbore.