A system for controlling for at least one string of a musical instrument by selectively exciting or damping vibration of the string is provided. The system includes at least one transducer configured to sense a lateral vibration of the string and/or to apply an actuating force to the string. A controller is configured to determine an actuating signal for driving the actuator to apply a longitudinal actuating force to the string at a termination point of the string. The longitudinal actuating force are operable to modulate a tension of the string that increases and/or damps the lateral vibration and/or selected harmonics thereof.