Watching a movie in theaters gives a different viewing experience compared to watching a DVD at home. Once the curtain rises and the lights dim, it seems like something magical is going to happen. Then you hear the surround sounds so loud and great it makes you feel like you are one of the characters in the movie. All of this was all made possible by how the theater is built and the acoustical materials used.
Building of theatres involved materials that allow noise to be controlled. There are four types of noise control. They are Sound Insulation, Sound Absorption, Vibration Damping and Vibration Isolation. Sound insulation is the first type of noise control. Sound insulation happens when a solid barrier is used in a work space to mitigate the amount of noise and vibration inherent to its environment. The idea behind is the harder the solid barrier to infiltrate, the more efficient it will be as a form of noise control. Materials such as steel and concrete are often used for this purpose. The second type of noise is Sound Absorption. This happens when the energy in sound waves is transformed into heat. The most effective choice for this process is porous materials. They can absorb the excess sound in the surrounding air. Next is Vibration damping. Like sound absorption, vibration damping relies on energy conversion. But instead of sound waves, vibration damping transforms excess noise and vibration associated with solid surfaces. The fourth type of noise control is vibration isolation. This process is used to protect an area from unwanted noise or vibration. The most common method of accomplishing this is adding a physical barrier.
For noise control to be effective, specific acoustical materials must be used. You must know the purpose of each material like if it will be used as an absorber such as fabric wall panels or a sound proof door as a noise barrier.