An audiometry exam tests your ability to hear sounds. Sounds vary, based on their loudness (intensity) and the speed of sound wave vibrations (tone).Hearing occurs when sound waves stimulate the nerves of the inner ear. The sound then travels along nerve pathways to the brain.Sound waves can travel to the inner ear through the ear canal, eardrum, and bones of the middle ear (air conduction). They can also pass through the bones around and behind the ear (bone conduction).The INTENSITY of sound is measured in decibels (dB):A whisper is about 20 dB.Loud music (some concerts) is around 80 to 120 dB.A jet engine is about 140 to 180 dB.Sounds greater than 85 dB can cause hearing loss after a few hours. Louder sounds can cause immediate pain, and hearing loss can develop in a very short time.The TONE of sound is measured in cycles per second (cps) or Hertz:Low bass tones range around 50 to 60 Hz.Shrill, high-pitched tones range around 10,000 Hz or higher.The normal range of human hearing is about 20 to 20,000 Hz. Some animals can hear up to 50,000 Hz. Human speech is usually 500 to 3,000 Hz.