Your capacity to hear sounds is evaluated by audiometry. Based on their volume (intensity) and the rate at which sound waves vibrate, sounds differ (tone). Sound waves cause the inner ears nerves to fire, which results in hearing. The sound then makes its way to the brain via nerve connections. The ear canal, eardrum, and middle ear bones are all possible passageways for sound waves to reach the inner ear (air conduction). They can also penetrate the bones behind and around the ear (bone conduction).