4 Basic Types of Noise Control – There are four basic types of noise control. They are sound insulation, sound absorption, vibration damping and vibration isolation. Each of these works differently and is better suited for some situations than others.
The first type of noise control is sound insulation. This occurs when a solid barrier is introduced to a work space in an effort to mitigate the amount of noise and vibration inherent to that environment. This solid barrier helps reduce the reverberation of the offending sound waves by blocking them. The more difficult the solid barrier is to penetrate, the great its efficiency as a form of noise control will be. As a result, very dense materials such as concrete and steel are often used for this purpose.
Sound absorption is based on the premise that energy can neither be created nor destroyed. Instead, it can only be converted into another form. With this form of noise control, the energy found in sound waves is simply transformed into heat. A reduction in noise is a natural by-product of this process because the conversion of sound wave energy into heat energy drastically reduces the amount of ambient noise left in the environment.
Not surprisingly, porous materials are the most effective choice for this process. Like a sponge, these materials are actually able to absorb the excess sound in the surrounding air. Therefore, highly permeable materials such as foam products are excellent for this type of application.
Vibration damping is used to control excess noise and vibration associated with solid surfaces, rather than from actual sound waves. This process works by extracting the vibrational energy from the surface material and converting it into heat energy. This method of noise control is similar to sound absorption in that it relies upon energy conversion rather than obstruction. However, like the other major forms of noise control, the primary purpose of employing vibration damping mechanisms is to minimize the impact of the unwanted noise and vibration on the surrounding environment.
Vibration isolation is the fourth form of noise control. As the name implies, this method involves protecting an area or its inhabitants from the source of the unwanted noise or vibration. Adding a physical barrier to the work space is the most common method of accomplishing this and can be quite effective as long as the barrier is able to adequately block the area to be protected from the source of the offending noise.