This article throws light upon the three main places causing noise pollution through pop music. The places are: 1. Restaurants 2. Discotheques 3. Open Air Festivals.
Place # 1. Restaurants:
Many four- and five-star hotels in the larger cities of India often provide live pop music to entertain their customers. In the case of restaurants or the dining halls of luxury hotels providing live pop music, the noise level is rarely nuisance to the neighbours. The only problem here is that the noise level is simply too high for the patrons to enjoy their meals with family or friends.
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If the level of music is too high, it interferes with the conversation and normal social intercourse. From this point of view, 75-80 dB (A) is about the acceptable limit for the sound level of music. In fact, there is a law in Sweden which states that no restaurant may play music at levels louder than 85 dB (A)
It is obvious that the noise level in restaurants should be kept down and the obvious solution is to limit the sound level of the pop band to a certain safe level. This, however, is a negative approach and one should try a more positive method. In a restaurant with a band, for example, there is usually a small dance floor immediately in front of the band.
When this is the case, one can solve the problem of loud noise partially by mounting the loudspeakers in such a way that the maximum level of sound is obtained on the dance floor and the minimum of it at the dining tables. This may be achieved by having a large number of high-quality loudspeakers mounted facing down from a low ceiling.
Theoretically, it is possible to put an acoustic screen, e.g., a glass screen extending from the floor to the ceiling, between the pop band and the dinners to reduce the noise level, if no other solutions are available. Even this drastic solution, however, may not be acceptable for other reasons. For example, if there is a cabret act, this solution is impractiable, since the cabret artists need to move freely among the audience,
Place # 2. Discotheques:
No general statement can be made about these establishments, since they vary all the way from a dark, dingy cellar to a large hall well lit, well run and capable of holding up to 5,000 people. The problems of noise control are vastly different for these extremes.
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In the case of cellar-type smaller establishments, investigators have recorded noise levels of up to 122 dB (A). Such high noise levels certainly damage the hearing of participants. To bring down these noise levels to more reasonable values, some sort of automatic electronic control must be fitted.
Disco enthusiasts, however, have no inclination or motivation to control the noise level in such establishments. The customers, management and the disc jockey all reinforce one another to keep the sound level unreasonably high. Only appropriate legislation and its strict enforcement can be of any help in such cases.
In addition to patrons and musicians, discotheques also cause problems for the neighbours. In the first place, neighbours may be affected by the structure-borne vibrations if their properties abut onto the discotheque. When this is the case, the problem of vibrations can be tackled with the help of standard architectural acoustics.
In the second place, when the neighbor’s property does not actually about onto the discotheque, the noise affecting the neighbours is clearly air-borne. Discotheques are notorious for improper sealing of their dance halls.
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In fact, they appear to go to great trouble to make sure that the noise does escape. Once again, the solution depends on good architectural acoustics, i.e., the sealing of all holes putting silencers over all air ventilators, use of massive solid doors and double glazing of the windows.
Place # 3. Open Air Festivals:
Open air pop festivals present a very special problem. Since such performances take place in semi-anaechoic surroundings, it is inevitable to use very large amplifiers. But the use of large amplifiers in the open air obviously implies that the resulting sound will travel considerable distances and cover wide areas. This produces many complaints from the neighbouring localities.
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To prevent this large radiation of noise, a novel and imaginative method was tried in 1974. The main features of this new method were the “long throw” speakers which are capable of giving relatively narrow beam widths of amplified sound. The audio spectrum of music was split into four components. The very low frequency sound is rapidly attenuated by the ground.
The same is true, to a lesser extent, of the mid-frequency sound. The very-high frequency speakers were mounted on the top of two towers and pointed in such a manner as to cover the audience. The mid-range speakers too were mounted on the top of these towers and were aimed in such a way that they would cover the whole arena, but not spread their sound outside the arena.
As a further measure to impede the radiation of sound outside the arena, a barrier in the form of a stout, solid, wooden fence, about two metres high was erected all around the ground. This arrangement was so effective that the number of complaints about loud noise dropped to about one percent of the expected number.