|
"Hum, hum, hum", "Bump, bump, bump", "Bang, bang, bang"...... Planes taking off, vehicles running on the road, wheels rolling along the track...... Modern people are living in a more and more noisy society. They can't stop suffering from Noise; they are eager for "Silence". |
 |
While, "Silence" is really we want? On the 37th International Congress and Exhibition on Noise Control Engineering (Internoise 2008), the experts unveiled the answer. Silence is not the ultimate goal of acousticians any longer. They call on "From Silence to Harmony". Experts in acoustic field have already broaden their definition of noise. They didn't only focus on the so-called noise any more; they began to turn their attention to the subjective feeling of human being, not only the measuring results tested by devices. It seems that the definition of Noise should be updated.
Silence is not equal to Comfort.
Generally speaking, silent space is the most ideal environment for work and life for most people. However, in recent years, it is found that silence doesn't mean comfort any more. For example, in some very quiet offices or rooms, when someone happens to make a small sound, just like drinking tea or flipping books, it also can make the people near around feel disturbed or uneasy. Scientists suggest that low and soft music could cover the unharmonious sound in such places. In this way, the room seems quieter and the people in it would feel much more comfortable.
"Nowadays Scientists pay more and more attention to people's feeling of sound. They emphasize the feeling of comfort and the control of noise annoyance instead of only caring about the db value," said Li Xiaodong, the technical chair of Internoise 2008 and professor of CAS Institute of Acoustics. "Usually we try to lower and control the noise. But to what extent? Nobody knows. It is a question of psychoacoustics and noise evaluation and it is a new direction of acoustic study," He continued.
According to Prof. Li Xiaoding, with the theme -- "From Silence to Harmony", Internoise 2008 aims to call on the scientists and publics to update the definition of noise control; pay more attention to the sound quality and annoyance of noise and people's feeling to noise (under the condition of no much cost added); R&D more related products and try to improve the sound environment of social life. "The fist plenary lecture of the congress is given by Prof. Harry Steven Colburn titled 'Binaural Hearing Mechanisms', which focuses on the subjective feeling of human being to noise," Prof. Li Xiaodong said.
Noise control -- Hi-tech products come out.With the development of noise control techniques, there are lots of hi-tech products have been developed abroad. For instance, the concept of microperforated panel was born in 1940s. Prof. Ma Dayou of IACAS put forward the approximate formula of high and low frequency in 1970s and made out some experimental samples. Since then, microperforated panel had been widely used in every field. Prof. Li Xiaodong said: "The structure of this material is very simple; the sound absorbing characteristics can be computed exactly, decorative material can be chosen freely according to different use and what's more important, microperforated panel is clean and non-pollutive."
Microperforated panel had been widely used in noise elimination and sound quality control devices, like microperforated panel muffler, jalousie, sound barrier and so on. The vitrification modification of Reichstag dome was a successful application of microperforated panel.
Noise control -- "We are still far behind."
"Our country's theoretical research on acoustics and related standards constitution can rank first in the international world, but our applications are still far behind," said Prof. Tian Jing, the President of Internoise 2008 and Director of Acoustical Society of China.
As early as 21 years ago, the 16th International Congress and Exhibition on Noise Control Engineering was held in Beijing. From then on, scholars in our country attended all the previous congresses. The level of papers was raised greatly as well as the number of attendants increasing each year. In this year's congress, there are all together 636 papers, among which 25% are from Chinese scholars.
"However, our ability of exploration and application has been upgraded so fast," Prof. Tian Jing said. He pointed out that only one Chinese enterprise exhibited its products in the latest congresses of Internoise. Most Chinese enterprises and those who use acoustic measurement devices don't pay enough attention to acoustic production exploration. "We hope the clients and developers at home could broaden their horizon through this congress. They can have a clearer mind on the hot issues of noise research in the international world."
Facing the problem of noise control, the whole society should join together. To the leaders of different level, they should renew ideas, pay more attention to the noise effect to human life and try to improve the sound quality of the society; to the entrepreneurs and the researchers, they should develop more acoustical products and provide a more enjoyable and harmonious sound environment for all the people.
(From Li Daqing, Science and Technology Daily)