From Wikipedia

Human Senses

Hearing And Balance

In biomechanics, balance is an ability to maintain the center of gravity of a body within the base of support with minimal postural sway. When exercising the ability to balance, one is said to be balancing.

Balancing requires concurrent processing of inputs from multiple senses, including equilibrioception (from the vestibular system), vision, and perception of pressure and proprioception (from the somatosensory system), while the motor system simultaneously controls muscle actions. The senses must detect changes of body position with respect to the base, regardless of whether the body moves or the base moves.

In the case of an individual standing quietly upright, the limit of stability is defined as the amount of postural sway at which balance is lost and corrective action is required. The limit of stability may be described by an irregular conical envelope above the support base. 

A balance board—which is an unstable standing surface that moves in different planes of motion—is commonly used to train balance.
Hearing or audition is the sense of sound perception. Since sound is vibrations propagating through a medium such as air, the detection of these vibrations, that is the sense of the hearing, is a mechanical sense because these vibrations are mechanically conducted from the eardrum through a series of tiny bones to hair-like fibers in the inner ear which detect mechanical motion of the fibers within a range of about 20 to 20,000 hertz, with substantial variation between individuals. Hearing at high frequencies declines with age. Sound can also be detected as vibrations conducted through the body by tactition. Lower frequencies than that can be heard are detected this way. The inability to hear is called deafness.