QUIET PLEASE

there are times when everyone demands quiet please ah yet without sound and the ability to hear it life would be entirely different it is essential to communication to understanding demands fulfillment in a civilized world only the death know the meaning of a totally silent world but too much so unpleasant unwanted sound is noise [Music] and every day more and more we are all prisoners of noise in city what's up on the farm outside or inside like other kinds of pollution noise is said to be the price we pay for economic progress every year the world will become louder and louder and let me conquer the scourge of noise what is sound two one fire common consists of variations in air pressure it travels on air waves similar to waves in water it penetrates metal even water four times faster than now physically sound in the air is produced by vibration caused by one solid hitting another by friction [Music] by Purdue or indirectly by resonance [Music] sound is powerful ultrasonics which only animals here can clean teeth or metal parts and discover flaws in materials audible sound frequently serves a useful purpose sound is analyzed from three aspects source that is the vibrating object transmission which must occur in some medium either gas liquid or solid and receiver which is your ear a miracle of miniature engineering the eardrum shaped like a cone of a loudspeaker receive sound vibrations connected to it are the three smallest bones in the body the hammer the anvil and the stirrup which transmits sound to the inner ear and amplify or modifies sound pressure in the tiny snail like inner-ear are thousands of microscopic hair cells the cells convert the mechanical properties of sound into electrical signals which is sent along the auditory nerve to the brain and on to every organ and nerve center the two main elements of sound are volume or amplitudes and frequency or pitch whether a noise offends the gear depends mainly on both volume and pitch volume is expressed in decibels three decibels represent the smallest change in sound detectable by the average gear to lawnmowers make quite as much noise as one or a three decibels increase for each doubling of the distance there is a six decibel decrease in amplitude a significant increase in noise is ten decibels let's listen to a few along the decibel scale [Music] over 120 decibels or some 100 billion times more energy than a whisper the ear feels pain frequency is measured in cycles per second the normal here is a range of pitch from 20 to 20,000 cycles the more frequent the vibrations the higher the pitch the gear is most sensitive to those frequencies between 1000 and five thousand cycles more than any other form of pollution noise is personal intermittent or unexpected noise often startles and frightened favoring the body one man's pleasure is another man's pain studies showed that the feeling of many teenage musicians quickly degenerates to the level of old folks noise-making has always been an expression of virility and beast an outlet for frustration a [Music] demonstration of power but when preventable noise disturbs the relationship between man and his environment or between man and man it is time to Yelp a quiet machine noise at home were at work is directly related to the number of fluffy [Music] The Stand exposure to noise of 90 decibels or higher can result in hearing loss and was more than 18 million people suffer it has become a major category of investing of injury which billions in compensation is rich [Music] the hair cells in the inner gear are helpless to protect themselves and once damage near a hearing aid nor an operation can restore the ability to hear earplugs or must reduce volume up to 35 decibels good verbal conversation requires talking found 15 decibels the bears background now more prevalent than hearing loss is the insidious cumulative effects of chronic noise on mind and body the stress caused by too much noise affects the cardiovascular system raising blood pressure and the amount of cholesterol in the blood excessive noise also results in mistakes and accidents at work headaches nausea and nervous tension irritability fatigue and sleeplessness for optimum sleeping the noise level should not exceed 35 decibels good sleepers may produce noise laugh and the world laughs with you snore and you sleep alone these are the unwanted sounds that constantly threaten man's sanity may fool yourself into thinking you can get a custom piece but your nervous system pays an exorbitant anything right citizens increasingly angered by noise clamor for abatement Robert Barron a pioneer fighter for quiet says air pollution kills us slowly but silently noise makes each day a torment local anti noise ordinances are proliferating difficult to enforce and in many cases ill-conceived due to ignorance more affected would be preempted uniform regulations state by state except realistic maximum noise levels New York in California became the first to regulate truck noise by limiting its 286 decibels at a distance is 50 feet the truck industry responded by meeting the standard but noise critic insist on even tougher laws they blame industry for noise standards that are too high [Music] resent the courts accepting noise annoyance as an inescapable part of 20th century life and reject the claim that noise abatement is a luxury we can't escape our vital transportation industry on which we depend for our daily survival has heard the message loud and clear the coming of commercial jet travel has turned airports in two major annoys centers pratt & whitney aircraft the largest manufacturer of aircraft engines in the world has made significant progress in noise reduction jet engine noise comes mainly from the exhaust and the fan the trust created to propel an airplane depends on the quantity of air passing through the engine and the jet exhaust the lucky the first turbofan engine reduced jet exhaust roar by about 10 decibels on takeoff but at the same time emphasized the high pitch single frequency tones from the fan during landing pratt & whitney's newest engine that powers the boeing 747 incorporates all the company has learned about noise control this super power plant produces more than twice the thrust it generates considerably less noise than earlier models traffic noises also of common law just as an aircraft noise from trucks is compounded of several different elements for the public blames the exhaust most of all ninety-eight percent of exhaust noise can be controlled contrary to popular myth properly designed mufflers did not rob engines of power or waste fuel too often truck noise buidling adequately or unlawful engines is unfairly blamed on one of the most important safety devices ever made for diesel vehicles the jacobs engine brake this retarder is a hydraulic attachment to the engine that converts it into a power absorbing air compressor it holds the truck at a steady speed without using regular brakes on any terrain going uphill trucks make this kind of sound [Music] the same trucks restrained by a Jacob's engine brake make a new sound approximately at the same level this is the sound of safety unnecessary noise to prevent runaway vehicles and action but this new sound can be controlled by proper muscle in cooperation with other manufacturers jacobs has solved its noise problem with an integrated muffler design other sources of truck noise must also be identified and control the same the engine itself which in this test is being operated without fear to demonstrate the sound of its moving price the transmission and drivetrain and tired the wine of which increases with load and speed hear a truck coast with engine off tire noise can be reduced with better tread design also asphalt is a quieter surface and concrete to decrease total truck noise even slightly below legislated standard requires a reduction of all out not just one or two plus the human the driver himself America's quietest city Memphis and earn this honored as the result of a vigorous educational campaign against blowing horns moreover all of its city buses are equipped with jacobs engine brakes even with better laws and stricter enforcement noise cannot be legislated out of existence it must be designed out as pratt & whitney and jacobs have done so must engineers in every industry designed for quiet using a from the ground up systems approach first minimize noise at its source by enclosing muffin eliminating vibration surface damping balancing as compared to an unbalanced impeller reducing turbulence or air flowing around and against the surface machine noise is unnatural quieter more efficient machines like this seat blower for an Airbus last longer and cost a little more to make better design can also reduce transmission of noise by using materials that act as sound barriers or absorb most of the sound by changing frequency and by substituting plastics for metals the path of noise is either structures or airborne this cam causes a structure borne vibrations transmitted to a piece of sheet metal which in turn becomes a source for airborne noise third by the year outside noise can be diluted by screening highways with dense vegetation quiet zones in cities where no traffic is permitted to press through ways noise research is mushrooming at the University of Hartford and anechoic or non echo chamber simulates the free space of the sphere making possible to study of noise transmission according to bargain frequency and direction under contract with local companies the Department of Mechanical Engineering analyzes the noise levels of various products and assists in the redesign of components to reduce or eliminate the most objectionable noises quieting clanton or for some of the largest industries the United acoustic insulting demonstrates a very noisy pneumatic hammer chiseling off a rough spot on a track detecting the hammer itself has to be quieted then the casting resonance again to further reduce the noise to the limits of the Walsh pili act cloud and whitney aircraft pursues its quest for further noise suppression on outdoor tested in its laboratory and giant supersonic wind tunnel in the tauren corporations well-equipped sound labs a Hotwire probe a super sensitive instrument measures the air velocity of an air conditioning fan and this machine tests for revenues our world is small people are many and everywhere unwanted sounds multiplying and Delta they annoy aggravate disrupting truth hurts and impaired at the same time Manning welcomes pleasant sound for contemplation for serenity [Music] renewing this is well-being privacy is a basic human need and vital to achieving a better saner life indispensable in making sure we not the machine come first is now Garrett you may resize and noisy no Ivan noise a nice trip what did you say I know I didn't know eyes are noisy oyster what does that mean or just don't like noise either the engine brake division of the jacobs manufacturing company has produced this film in the public interest in trying to overcome our own noise problems we have become aware of the significant lack of knowledge on this subject by government officials legislators and the general public we hope this film will create a better understanding of the noise problem