The technology to make machines quieter [br] [originaltext] As we all know,

As we all know, when machines work they give off a lot of noise. And the noise can sometimes be very unpleasant or annoying. As a result, people have been trying to find ways to reduce noise. Although it may sound a little bit strange to you all, one of the best ways to make machines quieter, in cars, for example, may be to make them noisier. The source of this paradox is electronic anti-noise, which creates sound waves to cancel out unwanted noise, such as rattles, blares, etc. Now although the idea dates back to the 1930s, it’s only recently that the advances in computer technology have made anti-noise a commercial possibility. Take France for example. Here industry spends a fortune to get rid of noise. We all know how unpleasant it is, for people working in factories and ordinary people at home enjoying their leisure can be affected by noise. Delicate machines are affected by noise as well. The government has passed a lot of regulations concerning acceptable levels of noise.
    Noise is costly to industry. In the first place, just following a single regulation can cost one to two billion US dollars in the textile industry, they say. Then secondly, of course, vibration can cause damage to machinery. Even very small vibrations can cause parts to wear out and equipment to fail. And naturally enough this gets onto the price of the product. About 5-15% of the price of a product comes from noise and vibration cost, as estimated. At present, methods used to dampen down noise and vibration rely on techniques that are thirty or forty years old. These usually involve wrapping the noisy or vibrating component in anything from cotton to concrete.  But it is often expensive and inefficient. The modern electronic anti-noise devices don’t reduce sound. Instead, sound is used to attack sound. The trick is to hit this sound wave with other waves in a carefully controlled way. It may not be possible to eliminate the noise completely. But engineers can build systems to eliminate specific kinds of noise and vibration. The new systems can deal with repetitive noise. This unfortunately means that there is not much that can be done about one of the noise, like someone trying to learn to play trumpet, but they can handle fairly regular things, like engine noise.
    A French company has developed a technique which uses microphone and the micro- processor. The processor measures the sound and directs the speaker to broadcast sound waves that are out of phase with the engine noise. The company claimed that it would make the car engine quieter, if not completely 100% silent. There are a number of other areas of application in the noisy industrial environment of today. One system which the company is developing is to minimize the noise of aircraft engines and helicopter vibrations. Now anti-noise systems will be able to reduce noise in a cabin of an airplane to more acceptable levels. Another area which affects ordinary household nowadays concerns the noise which electricity and gas fires create. The electricity companies spend a lot of money each year cutting the harm of transformers, trying to quiet the noise and maintaining the equipment that is constantly affected by vibrations.
    If they can get rid of or even stop the vibrations, manufactures can increase the production speed. But of course people working in noisy work places are perhaps more affected than anything by the effects of noise. Anti-noise can also create zones that are quiet in noisy work places. To create such a zone, you do two things. First, microphones are suspended around the work place. Then, speakers that produce out-of-phase sound waves can then be put closer to the worker under the desk or the machine. A company working in this area has tested this system and said that the car’s noise level is low enough for somebody inside the zone to hear a conversation from another part of the work place. Yet this is only one way. Shouts from a quiet zone could not be heard over the factory noise by those outside it, because the rest of the work place remains noisy. This is one of the anti-noise measures experimented with today. If this proves to be feasible in many work places, I’m sure it can contribute to the reduction of the noise in factory workshops in the future.