Vibration can be considered as a mechanical wave. These waves are generated by artificial and natural sources and they are propagating through mechanical structures via different propagation paths.  The picture below shows a typical example. Mechanical waves generated by traffic and internal machinery propagate through the ground to the supporting elements of the building. For static reasons the join connection between the ground and the supporting elements is designed in a rigid manner. Therefore most of the incoming wave is transmitted to the building. Following the propagation path the wave excites the floor and walls. Finally all structures inside the building, e.g. laboratory tables and workstations, will be excited by the structure borne sound as well. Depending from the excitation frequency and the material of the wall the structure borne sound can be transferred into air borne sound as a secondary transmission path.