Sound barrier technology refers to the ability to keep the sound in a room from spilling over into existing rooms or structures. It also refers to the ability of a structure or room to keep outside sounds from entering the room. Sound barrier technology refers to the physical characteristics of materials and how they are arranged to prevent sound and vibrations from transmitting through them.
Sound barrier technology consists of materials that have different densities and these materials are arranged in a manner that contributes to reducing vibrations from the electromechanical energy of speakers and any other sound generating device. It is the arrangement of these materials and their respective densities that is the key to producing a good sound barrier. An air space between the layers of different materials is also used to isolate vibrations.
The best way to isolate sound is to build a structure within a structure that is decoupled physically from each other. The Russian doll with a series of smaller dolls inside is an example of good sound barrier technology. Each doll is a separate physical structure set within another doll.
Sound barrier technology has a rating called STC. STC stands for sound transmission class and refers to a structures ability to minimize sound transmission through it. A STC rating of 55 would be a good rating for a door in a recording studio. A STC rating of 60 would be a good rating for a wall within that same studio.