Hearing Loudness or Sound Amplitude
by Ron Kurtus (revised 25 November 2003)
Humans and animals sense a wide range of sound amplitude, volume or loudness—from the very quiet to the extremely loud.
This range of amplitude affect the person's or animal's perception of the world, as well as its ability to communicate.
Questions you may have include:
- What are the amplitude limitations?
- How does it affect perception?
- How can I enhance my capabilities?
This lesson will answer those questions.
Your ears can detect the loudness or amplitude of sounds within a certain range, from the very quite to very loud.
Measurement of loudness
Loudness is measured in decibels, which really measures the energy of the sound. Each 10 decibels increases the energy by 10 times. In other words, 20 decibels has 10 times the energy of 10 decibels, and 30 decibels has 100 times that of 10 decibel.
A human can hear from very quiet sounds at 0.1 decibels to sounds at 120 decibels, which actually can cause pain. At the high end of the scale, the energy can cause damage to the sensitive membranes in the ear.
Danger of loud sound
Listening to very loud music can start to permanently damage hearing.
This is a problem with many rock musicians, as they start to go deaf from their own musicthus forcing them out of their business. People who sit in front of the speakers during a concert often suffer loss of hearing for days afterwards. For some, the damage and injury to the hearing can become permanent.
Another potential hazard is in using earphones if the volume is cranked up too high. Since the earphones are directly against the ears, there is not buffering and high intensity sound waves blast directly on the eardrum.
One big problem is listening in a noisy environment, like in an airplane. In order to overcome the background noise, the person will increase the volume to a dangerous level. There are noise reduction earphones that damper the outside noise, so that the volume does not have to be so high.
Inexpensive earphones often do not filter out spikes of sound that are of a very high volume, but they happen so quickly that you dont even notice them. There are theories that they could possibly do damage to the hearing.
Some can hear low volumes
Younger people can usually have better hearing at the lower volumes than older people do.
For example, when I was 15 years old, I noticed that our blinking Christmas lights made a slight buzzing sound before they blinked. This is because such lights usually have a tiny micro-switch, which turns the electricity on an off. It would buzz during the switching process.
I could hear with the lights switched on or off across the room, with my back facing the lights. Meanwhile, adults would have trouble hearing the sound with their ear up close to the lights. This is not to mean that my hearing was so fantastic. Rather it is to show how age diminishes the ability to hear low volume sounds.
Animals hear low amplitude
Animals can hear lower volumes and are more sensitive to louder noises than humans.
One reason is because of the way their ears are shaped. Cats are an example of an animal that has ears that gather in sound and focus it into the ear channel. They use the ability to hear quiet sounds to catch mice and such.
You can increase your ability to ear low volumes by cupping your hands by your ears. Your hands are reflecting the sound into your ear channel just like the cats ear reflects sound for them.
Hearing affects perception
What you can hear affects your perception of the world. You may not hear the very quiet sound that some animals can hear. For example, an owl can hear the rustling of a mouse under the snow in the winter time.
Vital in communications
If your ears are very sensitive to low volume sound, you might be able to hear things that an ordinary person couldn't. On the other hand, loud noises may disturb such a person.
A deaf person misses the joy of hearing music, as well as having problems with communication.
Filtering extraneous sounds
There is also part of your brain that filters out extraneous sounds. In this way you may be able to be in an noisy environment, but be able to concentrate and not be distracted by other sounds. Filtering out the din and non-important sounds is important in maintaining a good hearing balance. Some people are unable to filter out unimportant sounds, such that they hear everything--different noises and hums and dogs barking--that we normally ignore.
There are also devices that put out a random noise--like static--that is called "white noise" and is used to help your brain filter out such sounds as the neighbor's TV.
Enhancing hearing sensitivity
It is difficult to improve what you were born with, but you can become more alert to subtle and quiet sounds. You can go in a quiet place and try to hear things most people would not be able to hear.
You should also try to avoid loud noise situations that can damage your hearing.
Animals and humans can hear sounds in limited range volume or amplitude. Some animals can hear sounds that humans cant. Very high volume sounds can cause pain and damage to a person's hearing. People filter out extraneous sounds.
Soft speaking sooths the beast
Resources and references
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