Airborne sound is transmitted through the air and can be attenuated by the use of barriers and walls are physically between noise and receiver. Structure borne sound is generated with the help of vibrations induced in the first and/or structure. These fluctuations excite walls and floors in buildings and cause them to radiate noise. This type of noise can be attenuated by obstacles or walls, but needs intervention sustainable break between the source and receiver. A large pipe, for example, suspended by springs from the ceiling, can significantly reduce the structure borne sound and vibration in adjacent rooms.
When airborne noise in the room, compressor or another machine, it can be transferred to adjacent rooms through a number of pathways for the transmission of walls, floors, doors and the overall structure of the building. Sound insulation characteristics of material structure is called the Sound Reduction Index (SDI) (sometimes called Sound Transmission Loss [dB]). The more SRI-sections, the better soundproofing. Since SRI depends on the frequency, the average SRI above frequency band is often used to assess the performance of various materials.
In simple sheet panels, where both open surfaces are rigidly connected, when the weight per unit area increases, SRI increases.
This relationship between the masses and the SRI Weight of the Law and noted that in theory there are approximately 6 dB SRI increase for each doubling panel mass or for each frequency doubling. In practice, the actual increase rate is about 4 dB. Higher values of insulation can be achieved through the use of two (or more) sheet panels with a cavity between them. To achieve significant advantages of low-frequency cavity width should be not less than 150 mm In the cavity, porous materials should be hanged, for example, mineral wool and fiberglass mats. He noted that to achieve high performance in the overall structure, good sealing between the panel connections required. Some codecs can be equipped with sound proof that significantly reduce the acoustic leaving the source. Silencers specialist field, and expert advice that may be required in the case of specific problems...
Air-Conditioning