An energy attenuation apparatus for a system conveying a liquid under pressure is provided. The apparatus includes a liquid-conveying unit or the like that includes three chambers disposed in series. At least one of the chambers contains no tube. A first tube is disposed in one of the chambers and has a first end connected to and in fluid communication with an inlet or outlet end of its chamber. A second, free end of the tube is spaced by an open gap from the outlet or inlet end of such chamber. The tube has at least one aperture in the free end and/or on the peripheral surface thereof for providing fluid communication between the tube and its chamber. A second tube can be disposed in the remaining chamber.