When we refer to noise, it is usually in the context of unwanted sound energy. The word noise has a negative connotation. Most of life’s noise we want to keep out of our rooms or contain the noise within the room or space it is generated in and keep it from leaking into other rooms.
A noise barrier would refer to some type of system which would prohibit noise from leaving or entering a room. A noise barrier technology is not to be confused with sound absorption technology. Sound absorption technology deals with absorbing energy inside of a room. Noise barrier or any sound barrier technology refers to the inhibiting of sound from entering a room or leaving the room and going into adjacient rooms or structures.
Noise barrier technologies are complicated and difficult structures to build. One must isolate the mechanical vibrations that sound produces through a series of layers of different materials and air spacing. Most noise barrier technologies must be physically decoupled from existing structures, so that sound vibrations are not transmitted to surrounding structures.