Prevent the spread of the direct sound, and the sound system has sufficient attenuation shot while transmitting sound effects are negligible. Therefore, sound effect sound barrier noise reduction amount may generally be said that it reflects the sound through the sound barrier above two shield skills. Between the sound source and the receiving point insert a sound barrier, set up a barrier of infinite length, acoustic diffraction in the past only from the top of the barrier, and in the subsequent formation of an acoustic shadow zone, as the light is blocked by the formation of a shadow object that. In this acoustic shadow area, people can feel the noise is significantly reduced, and this is the sound barrier noise reduction effect. Classification and structure of the sound barrier sound barrier classified into traffic noise barriers, equipment noise attenuation barriers, industrial plant sector barriers application environment based on sound barriers, sound barrier. Sound Barrier Material classification can be divided into the following categories: metal sound barrier (metal louvers, metal mesh hole), concrete sound barrier (lightweight concrete, high strength concrete), PC sound barrier, fiberglass sound barriers. Use can be divided into several categories: railway sound barrier, highway sound barriers, sound barrier urban landscape, residential noise reduction barriers. Sound Barrier outdoor sound barrier generally use brick or concrete structures, interior sound barrier cited steel, wood,, PMMA / POLYCARBONATE SHEET plastic plate, gypsum board and foam and aluminum structures. Sound barrier mainly consists of two parts, steel columns and absorbing insulation panel composed of the column is the main force component sound barrier, which is fixed by bolts or welding on a road or rail side of anti-wall embedded steel; absorbing insulation acoustic absorption panels are the main component, which through high-strength spring clips to secure it in the H-column tank, forming a sound barrier. Sound barrier has been designed to more fully consider the elevated highway, crash safety urban light rail, subway wind load, transport vehicles and all-weather outdoor corrosion problems. It is nice shape, producing exquisite, easy to transport, install, low cost, long life, especially for the elevated highway and urban light rail, subway use anti-noise, is a modern city ideal acoustic noise reduction facilities. Sound barrier height 5m 1m a room, covering the regional average effective noise reduction up to 10 ~ 15dB (A) (125Hz ~ 40000Hz, 1/3-octave), up to 20dB (A). Generally speaking, the higher the sound barrier, or farther away from the sound barrier, noise reduction, the better. Frequency, distance and height of the sound source and the receiving point barrier between the sound barrier sound barrier sound insulation and noise reduction amount of noise factors. A large component of the noise reduction effect relationship between the sound barrier and noise frequency of greater than 2000Hz frequency sound than the noise reduction effect of about 800 a 1000Hz IF sound better, but for about 25Hz low frequency sound. Since the acoustic wavelength is relatively long and can easily diffracted from the top of the barrier in the past, so the effect is poor. Typically, the sound barrier can reduce the high frequency sound l0-15dB. The height of the sound barrier, according to the height of doubling the distance between the sound source and the receiving point of the design, barrier, its noise can increase the amount of 6dB, in order to make better noise barrier should try to keep close to the sound barrier source or receiving point.