Abstract: Structure vibrations and structure borne sound may be reduced by passive and active isolation, by passive and active vibration and sound absorbers or by active control. The experiment presented in this paper is a part of an ongoing research project connected with the structural acoustic control in fluid loading structures. The paper presents the opportunity of active control of vibrations and sound through the application of a circular plate containing distributed piezoelectric actuators and sensors. The plate is supported on the edges in a rectangular enclosure and is loaded on one side by heavy fluid (sweet water) and on the other side has contact with a gaseous medium (air). Piezoelectric elements are arranged in sets, each containing four elements located on two concentric circles with different radii.