Normal hearing and impaired hearing
The actual organ of hearing is the cochlea in the inner ear. The cochlea receives sound waves and passes them on to the brain. This works smoothly in people with normal hearing.
The ears receive sound waves and change them into signals which are sent along nerves to the brain. The brain then analyzes the signals, recognizes them as sounds and interprets them: as soft music, for instance, or as loud honking or human voices.
Sound waves are created when an object moves, for example when a guitar string or loudspeaker membrane vibrates. Whether we hear a sound depends both on the power of the sound (“sound level” or “sound pressure level”) as well as on the frequency (or “pitch”) of the vibration.