With impact noise, the vibrations of sound are traveling through a medium other than the air. Impact noise is able to travel through structures, and so it is sometimes called structure-borne noise. When an object makes contact with another object, if the collision is strong enough and there is a direct line that the sound can travel from the area of impact to the room you are in, you will experience impact noise. Examples of impact noise include a construction jackhammer, a ball bouncing on the floor above you or water sloshing through your pipes.