How Hearing Functions

Hearing - Understanding Hearing Loss

How does hearing work?

Sound waves travel down the ear canal and hit the eardrum, causing it to vibrate. These vibrations set the fluid of the cochlea into motion which stimulates 15,000 sensory cells, called “hair cells”, that convert the vibrations into electrical signals. The brain processes this raw data, making it possible to hear and enjoy things like music or an engaging conversation.

Physiology of hearing

Your ear can be divided into 3 parts.
The outer ear and middle ear help collect and amplify sound.
The inner ear converts sound waves to messages
That are sent to the brain.


Sound waves are like ripples created on a pond’s surface when it is disturbed by a stone. Sound waves, like ripples, move out as differences occur in air pressure (compressed air and rarefied air). When these fluctuations hit the eardrum, they manifest as sound.

Sound travels as waves of pressure through air at a speed of 740 miles (approx. 1184 km) per hour. There are two features of sound that we can measure — pitch and intensity.

Pitch, also known as frequency, is a measure of how rapidly the waves change from above to below the ambient pressure. In other words, it is a measure of how many crests pass a point in a second. The greater the number, the higher is the pitch.

Intensity (loudness or amplitude) is a measure of how far the waves are above or below the ambient pressure. The greater the amplitude, the louder is the sound. Pressure levels of sound are measured as decibels (dB).