Fluid-dynamic noise in hydraulic systems has gained high attention in the last decades due to the increasing requirements of vibration and noise reduction in many fields. Usually the most significant sound sources in the system are fluid machines such as centrifugal pumps, in which flow pulsations are generated with amplitude that depends on the operating conditions (velocity and flow-rate). The resulting pres-sure fluctuations induced at a given frequency and position along the pipes also depend on the acoustic response of the system, i.e., on how the acoustic pulsations are transmitted or reflected at each system component, including the pump itself. Therefore, the direct meas-urement of pressure pulsations in a pipeline of a test pump does not directly reflect the acoustic properties of the pump itself, because the coupling effects of the hydraulic system, which can even cause standing waves, may be seriously misleading.