The part of the ear responsible for amplifying sound vibrations is called the middle ear, which consists of three pieces called the hammer, anvil and stirrup. The middle ear mechanically converts sound waves into more forceful vibrations.
Sound vibrations are initially collected through the outer ear and channelled to the eardrum, which separates the outer ear from the middle ear. Once the middle ear has amplified the pressure of the sound waves, the vibrations pass into the cochlea of the inner ear. According to the frequency theory of hearing, neurons in the cochlea fire at the frequency of the sound waves, allowing us to discriminate between various tones.