Webster defines noise as a “a sound that lacks agreeable musical quality or is noticeably loud, harsh, or discordant.”
Noise produces sound waves, which are uneven and jagged in appearance whereas music sound waves are even and flowing.
The intensity of a noise is measured in bels, a unit named after Alexander Graham Bell. A decibel is one tenth of a bel. Theoretically, the threshold of hearing is zero decibels, but this is only accomplished in experimental conditions.
i.ytimg.com
ADVERTISEMENTS:
“Silence” is normally around 25 decibels. Pain is inflicted (depending on the quality and pitch of the sound) at about 120 decibels. Severe pain and temporary loss of hearing are inflicted after only a few minutes at 140 decibels or a few seconds at 150 or more decibels.
Daily, in cities, one hears horn blasts, squealing tyres, screeching brakes, mumbling trucks and trains, blaring television sets, the roar of automobile engines and jet planes, the throaty growl of motorcycles and blaring loudspeakers.
Even at night, cities and suburbs are rarely quiet. An indefinable low moaning sound prevails, often punctuated with the ear-piercing shriek of a siren.
ADVERTISEMENTS:
Noise has indeed become omnipresent. As more and more crowd into the sprawling urban areas, noise pollution threatens to escalate rapidly.
But why should it be virtually impossible, especially in highly advanced technological societies, to get completely away from the racket of civilization?
Robert Koch, Nobel laureate predicted: “A day will come when man will have to fight merciless noise as the worst enemy of health.”
Workers in a very noisy factory are found to have lost an average of 50 decibels of their hearing range by working 15 years at a 100 decibel noise level. This means that their normal threshold of hearing (20—25 decibels) had been changed to about 70 decibels. Normal conversation (60 decibels) had to be repeated louder at (70-75 decibels) for the workers to hear.
ADVERTISEMENTS:
Ninety decibels is a health hazard for an 8″hour-day environment. Louder work sites, such as the environment of a jet plane at the passenger tamp (115 decibels) would be dangerous to health after only 15 minutes. Beyond any of these limits lies permanent hearing impairment.
The subtle physiological and psychological side-effects of noise are drawing special attention now. Prolonged high intensity noises have been found to result in loss of hearing and even total deafness. Ulcers, severe headaches, stomach upset, aggravation of allergies and asthma and heart conditions, insomnia and emotional breakdown are, in certain cases, attributable to too much noise!
At the noxious effects of noise or at an unexpected or unwanted noise, the pupils dilate, the skin pales, mucous membranes drain, there are intestinal spasms, and the adrenals explode excretions. The biological organism, in a word, is disturbed.
The resulting internal wreckage caused by a screaming siren includes gastric ulcers, thymus gland atrophy, and over-stimulation of the adrenals.
A sudden doorslam has been shown to raise man’s blood pressure four times, higher than the reaction from a shot of morphine. The quantity of blood pumped by the heart may double under the stimulus of even the sound of a baby crying. The increased oxygen consumption that comes with rising blood pressure results in exhaustion and nervousness.
Experiments have shown that noise, which interferes with sleep, lessens the body’s resistance to disease and physical stress. Even those conducting the experiments were affected. One doctor said he could not hear his watch tick for three hours after one experiment. Another found that his subjects were unable to hear a whisper just 3 feet away.
The cumulative effect of noise may cause increasing irritability, anxiety, or a sudden emotional outburst. The latter reaction is typified by the man who comes home after a tense, harrowing day in a noisy office.
The home, he finds, is also noisy, with the television turned up loud and the children running around, alternately laughing and crying. The harried man impulsively reacts in wrath at the accumulated racket. The evening meal is subsequently very unpleasant.
Prolonged subjection to an unpleasant noise, or even a pleasant sound, which is too loud or which comes at the end of a harrowing day, can lead to mental disorganization.
Experts also blame noise, in part, for the increased consumption of alcohol, drugs, tranquilizers and sleeping pills in advanced nations. These people are turning to these escape commodities, in part, as an attempt to drown out or “turn off the noises they don’t want to hear.
Noise has steadily increased even inside the home. Background noise reaching into the home from the outside environment has risen from 20 to 45 decibels in the past forty years.
Add to this the introduction of new appliances and labour- saving machinery used in the modem home. Well-furnished modern home may have as many as 10 gadgets that make noise.
The noisiest place in the home is the kitchen. Today’s automated kitchen often reaches a decibel level of 80 – the same as the noise level made by heavy traffic. With a fan, grinder and juicer going all at once, the decibel level may go to 100.
No wonder the average housewife often feels “on edge,” jittery, fatigued and frustrated. Young people may disbelieve it, but highly amplified rock ‘n’ roll music is damaging to their hearing. The young who either play or listen to rock ‘n’ roll music at high intensity levels may pay a price in terms of eventual reduction of hearing.