A method of operating a vibratory testing apparatus is disclosed including providing a table frame with at least one vibrator attached thereto and attaching the at least one vibrator to a solenoid valve, wherein an input of the solenoid valve is connected to a pneumatic air supply and an output of the valve is connected to the vibrator. The solenoid valve is connected to a controller and a first control signal is sent from the controller to the solenoid valve for opening the valve and allowing a first burst of air to the vibrator thereby causing the vibrator to vibrate the table frame at a first amplitude. Then a second control signal is sent from the controller to the solenoid valve for opening the valve and allowing a second burst of air to the vibrator thereby causing the vibrator to vibrate the table frame at a second amplitude.