The Control of Noise
As noted in the section “Noise and its Effects”, there can be many adverse effects to noise. It is appropriate to have tools to reduce the exposure of humans to noise.
The sketch to the right illustrates the three components of noise that can be addressed. There is a noise source, which could be a leaf blower, or a jet aircraft, or a line of traffic, or factory equipment, etc. The noise propagates to the receiver via a noise path. This can be air-borne propagation of noise, but can also include transmission of noise through the ground or through building structures. The third component is the receiver, usually a human listener but could also be a microphone or array of microphones.
The best approach, if possible, is to reduce the noise emitted by the source. Improvements in source design can achieve significant reductions in emitted levels. As an example, for traffic noise, design improvements can be made to automobile mufflers or to traffic pattern controls.
The noise path can be addressed through structures such as berms or noise barriers. Inside buildings, the addition of noise absorbing panels can reduce the received noise levels.
If a human listener is at the receiver position, they can use hearing protection to reduce their noise exposure. If it is a microphone transmitting to a remote location, the noise can be reduced using a wind screen or through digital filtering techniques.