When the animal shifts its orientation, fluid in the statocyst moves the hairs in a particular direction, relative to the statolith, which moves at a different rate because of its inertia. This differential movement stimulates some hairs more than others and gives the animal a sense of the direction of the movement. The purpose of the statocyst is to give the animal a sense of equilibrium and it functions much like our inner ear system. These are generally located at joints and within muscles and are stimulated when the joint is bent or straightened and when the muscles are stretched. Proprioreception is critical to maintaining proper posture and coordination during movements.
Lobsters are also capable of producing and detecting low-frequency sounds.
Clawed lobsters produce a growl or rasplike sound by contracting a small sonic muscle in the base of the large antennae. Their purpose is completely unknown, but may have something to do with defense. They do not, however, possess the functional equivalent of ears and thus do not hear these sounds in the same fashion as we do. This question has been asked by many a person who tosses a live lobster into a boiling pot or slices the live lobster down the middle to bake stuff. The answer is not at all clear.