Human is the only species with a well-developed brain. It enables us to reason, learn and make prudent decisions. Unfortunately, human intelligence does not make them have the best senses. The humans have low sensory, olfactory along with auditory senses. Many animals have a very well developed hearing. They have the ability to hear acoustic wave for long distances than what we can perceive. The human frequency range is also limited as compared to what other animals can detect.
First, it is very important to understand how the human ear operates.
Perception and Measurement of Acoustic waves in the Human Ear
The human ear is made up of minute bones and cartilages. Acoustic waves are channeled into the ear through an opening via a tunnel. They finally make the eardrum (tympanic membrane) vibrate to the various frequencies. This oscillation generated are transferred to the ear bones including ossciles, malleus, incus, and stapes. The bones are then determined from the oscillations of these bones. These oscillations are measured using a unit known as the hertz.
My hertz is equivalent to 1cyle per second.
Ranges of frequency that human ear can detect
Human ears have the ability to detect acoustic vibrations in the range of twenty Hertz to twenty kilo Hertz. As you grow older the ranges of the higher frequencies start to constantly disappear. This can generally project a conclusion that earing range for older people is reduced while children can perceive acoustic waves in the whole frequency spectrum.
According to research, the start of loss of detection of high-frequency range starts at the age of eight. Technically, as you grow older your range of hearing reduces with time. This is contrary to other animals that have and established ear. The bats have a good ear, they can sense and decode sound in the ultrasound range. This is so because they use a sonar system for navigating obstacles at night.
The ear a sensory organ allows us to interact with the environment in a mystical manner. With the ear as a receptor, the brain acts as a decoder that interprets and relays information to us. Our hearing is very limited to distance. Near sound, sources are easily perceived while those far you may be faint or no signal is received at all.
The Human Hearing under Ideal Conditions
The human ear can detect a limited band of the audio frequency. If measured in a laboratory setting, the exact frequency range can be easily determined. Using audio frequency generator, the frequencies can be varied from a few hertz to tens of kilohertz. The results always for an average young adult range between 12 Hz – 20 kHz.
Men Vs Women Hearing Range
The fact that men and women are same is not true in terms of audio frequency responses. Women are reported to respond very well to high frequencies than men. However, the obvious is not true at lower frequencies as both men and women show the same response.
Scales for Hearing Range
There are basically two units for measuring hearing. The units are pascal (Pa) and decibels (dB). However, the latter is mostly used as it has relatively reasonable values rather than the former which uses incomprehensible values. The pascal scale measures the distance sound can travel per oscillation. On the other hand, decibel scale expresses the sound in the form of logarithmic scale.
In terms of pascal scale, for instance, human hear can detect between 20 uPa- 20,000,000 uPa.
Similarly, the equivalent logarithmic scale ranges between 0 dB -120 dB.
In general, the hearing range is not universal as people vary in hearing abilities. The values used as the standard range are just used for reference.