How do we hear? What are the different parts of the ear?

The outer ear that we see is not the end of the journey of sound waves; rather the sound signals travels through four other parts of the ear to finally reach to the processing center that translates it to meaningful audio. In total, there are five components of ear and each one has its own specific role in processing the vibrations emitted from a source.

The parts of the human ear include:

  • Outer Ear
  • Middle Ear
  • Inner Ear
  • Acoustic Nerve
  • Central Auditory Processing Centers

How the Human Ear Function

The functioning of human ear is complex and a lot of processes takes place in different parts of ear after it receives a sound signal and convert it into an audio signal. The sound waves are collected by the pinna before it is directed towards the ear canal. The sound waves passes through the canal to hit the ear drums. The interaction of waves over the ear drums causes it to vibrate. The vibration of the eardrum is further passed on to the middle ear. In this section, Stapes, smallest of the three bones of the middle ear, picks up the vibration and transfers in to the inner ear through the oval Window. In this section the vibrations travel in form of fluid waves within the cochlea over the perilymph fluid. The same is picked by fine hair cells that are sensitive to smallest change in the motion of the fluid of the cochlea. These sensory hair cells further transfer the signals to the brain which translates the signals into meaningful audio.

What is the audible sound range for human ear?

A healthy human ear is capable of picking sound that originates from sound waves that are within the frequency range of 16 Hertz to 16384 Hertz. The sensation of different frequency of sound wave is perceived differently and the following chart details the same.

Decibels Perception of sound
0 dB The lowest sound that can be heard by a healthy ear of an 18-year-old
20 dB Very soft whisper
45 dB Softly spoken voice
60 dB An average voice spoken
70 dB A loud shout
80 dB A loud motorbike that is driven on a narrow street
90 dB Lawn mower
100-120 dB Heavy metal rock concert
120-140 dB A jet engine within a range of 250 yards/td>