Does installing sound barriers work?

(1) the factory installed sound barrier effect, in this shows that there are two aspects: one is that inside the factory, if the installation is sound-absorbing factory internal effective noise reduction can reach 30 decibel noise barrier around this particular case needs to see a noise decibel level, there is distance, but the sound isolation barrier among the internal office area and production area, office area generally can be reduced to 40 db below the noise. The other is the outside of the factory, such as four-sided or single-sided sound insulation, behind the sound barrier test, noise volume is not more than 50 db.