Interferenzleitung / Quincke Tube
The Quincke Tube is an arrangement that splits flow equally between two lines of analytically selected lengths. The two flows are then recombined at a downstream junction. The device works because the two flows are out of phase when merged because they travel different distances. A fundamental frequency and its harmonics can be cancelled out with this type of line arrangement .
 Akers, A., Gassman, M., and Smith, R., 2006, "Hydraulic Power System Analysis", CRC Press - Taylor & Francis Group, ISBN: 0-8247-9956-9, pp. 354