The human ear can detect sounds of varying frequencies. The outer part of the ear is called the pinna, which collects sound and channels it into the auditory canal.
When sound waves reach the eardrum, they cause it to vibrate; in turn, this vibration moves three small bones located within the middle ear (the hammer, anvil, and stirrup).
Vibrations are transmitted to the inner ear through fluid contained within a snail-shaped structure called the cochlea. These vibrations stimulate hair cells located on top of the basilar membrane in each chamber of the cochlea, which then sends information to the brain.
The cochlea is covered by a thin membrane called the tectorial membrane, which amplifies vibrations and increases the sensitivity of the inner ear.
Hearing Mechanism Explained
The hearing mechanism of the human ear can be described using three terms: amplitude, frequency, and phase. Amplitude refers to the loudness of a sound; it is directly proportional to intensity.
Frequency denotes the pitch or number of cycles per second (Hz) produced by a sound wave; high-pitched sounds have higher frequencies than low-pitched sounds.
Phase refers to the time at which partials of a sound reach the ear. In addition, because our ears respond differently to high and low frequencies, we can compare different parts of a spectrum by comparing the amplitudes of their harmonics. To do this, one must calculate the amplitude of a partial by measuring its peak response at different frequencies.
The ear does not perceive all frequencies equally. An equal-loudness contour is a curve that represents the loudness of different frequencies at the same level; this shows how much more sensitive our ears are to some pitches than others.
A sine wave can be used to calculate an equal-loudness contour. A sine wave can be used to calculate an equal-loudness contour.
The amplitude of each partial is plotted as a function of frequency, and these amplitudes are then averaged, resulting in a curve that represents the loudness at different frequencies for any given level.
Conclusion: Hearing Mechanism in Humans
The human ear is a very complex organ that can respond to sound waves of various frequencies and intensities. The outer part, the pinna, collects sound energy; it channels these vibrations into the auditory canal and then on to three small bones in the middle ear called hammer, anvil, and stirrup.
Sound vibrations produced by the hammer, anvil, and stirrup are transmitted to the fluid inside a snail-shaped structure called the cochlea. The basilar membrane is then stimulated.
The hairs on the top of this membrane vibrate in response to sound waves; these vibrations are amplified by the tectorial membrane, which acts as a diaphragm and amplifies the vibrations.
The cochlea is lined with hair cells that transmit information to the brain through nerve fibers when stimulated by sound waves.
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