Noise control is an active or passive means of reducing sound emissions, often incentivised by personal comfort, environmental considerations or legal compliance. Practical and efficient noise control is wholly reliant on an accurate diagnosis of what is causing the noise, which first involves finding the source of noise. Once the source of noise has been found, the focus is reducing the noise at source by engineering means.
The most common noise sources can be divided into aerodynamic (fans, pneumatics, combustion, etc) and
mechanicalA machine is any device that uses energy to perform some activity. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work. A simple machine is a device that transforms the direction or magnitude of a force without consuming any energy...
(impacts, friction, etc).
Noise control is an active or passive means of reducing sound emissions, often incentivised by personal comfort, environmental considerations or legal compliance. Practical and efficient noise control is wholly reliant on an accurate diagnosis of what is causing the noise, which first involves finding the source of noise. Once the source of noise has been found, the focus is reducing the noise at source by engineering means.
The most common noise sources can be divided into aerodynamic (fans, pneumatics, combustion, etc) and
mechanicalA machine is any device that uses energy to perform some activity. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work. A simple machine is a device that transforms the direction or magnitude of a force without consuming any energy...
(impacts, friction, etc). Effective noise control focuses on reducing the noise from these sources as close to the source as possible. Noise control for aerodynamic sources include quiet air nozzles,
pneumatic silencersThe word silencer can mean:* A suppressor that goes on the end of a firearm barrel* Silencer or muffler on an internal combustion engine's exhaust pipe* A sound-reducing device located in a large chimney* Silencer , a type of regulating DNA sequence...
and quiet fan technology.
In
architectural acousticsArchitectural acoustics is the science of noise control within buildings. The first application of architectural acoustics was in the design of opera houses and then concert halls. More widely, noise suppression is critical in the design of multi-unit dwellings and business premises that generate...
and
environmental acousticsNoise pollution is displeasing human-, animal- or machine-created sound that disrupts the activity or balance of human or animal life. The word noise comes from the Latin word nausea meaning seasickness....
,
noise control refers to the set of practices employed for
noise mitigationNoise mitigation is a set of strategies to reduce noise pollution. The main areas of noise mitigation or abatement, are: transportation noise control, architectural design, and occupational noise control...
. Within architectural acoustics these practices include: interior sound reverberation reduction, inter-room noise transfer mitigation and exterior building skin augmentation. More specific architectural noise control methods include the installation of acoustical gypsum, ceiling tiles, ceiling panels, carpet and draperies. In the field of environmental sound, common noise control practices include: design of
noise barrierA noise barrier is an exterior structure designed to protect sensitive land uses from noise pollution...
s, development and enforcement of noise abatement legal codes and urban design.
Types of noise control
There are four basic principles of noise control:
- Sound insulation: prevent the transmission of noise by the introduction of a mass barrier. Common materials have high-density properties such as brick, concrete, metal etc.
- Sound absorption: a porous material which acts as a ‘noise sponge’ by converting the sound energy into heat within the material. Common sound absorption materials include open cell foams and fiberglass
- Vibration damping: applicable for large vibrating surfaces. The damping mechanism works by extracting the vibration energy from the thin sheet and dissipating it as heat. A common material is sound deadened steel.
- Vibration isolation
Vibration-isolation is the process of isolating an object, such as a piece of equipment, from the source of vibrations.-Passive isolation:Passive vibration isolation systems consist essentially of a mass, spring and damper ....
: prevents transmission of vibration energy from a source to a receiver by introducing a flexible element or a physical break. Common vibration isolators are springs, rubber mounts, cork etc.
Materials used in architectural acoustics
Acoustical wall and ceiling panels can be constructed of many different materials and finishes. The ideal acoustical panels are those without a face or finish material that interferes with the acoustical infill or substrate. Fabric covered panels are one way to maximize the acoustical absorption. The finish material is used to cover over the acoustical substrate. Mineral fiber board, or Micore, is a commonly used acoustical substrate. Finish materials often consist of fabric, wood or metal. Fabric can be wrapped around substrates to create what is referred to as a "pre-fabricated panel" if laid onto a wall, and require no modifications. Prefabricated panels are limited to the size of the subas "on-site acoustical wall panels" This is constructed by "framing" the perimeter track into shape, infilling the acoustical substrate and then stretching and tucking the fabric into the perimeter frame system. On-site wall panels can be constructed to work around door frames, baseboard, or any other intrusion. Large panels (generally greater than 50 feet) can be created on walls and ceilings with this method.
See also
- Active noise control
Active noise control is a method for reducing unwanted sound.- Explanation :...
- Architectural acoustics
Architectural acoustics is the science of noise control within buildings. The first application of architectural acoustics was in the design of opera houses and then concert halls. More widely, noise suppression is critical in the design of multi-unit dwellings and business premises that generate...
- Noise Reduction Coefficient
The Noise Reduction Coefficient is a scalar representation of the amount of sound energy absorbed upon striking a particular surface...
- Noise mitigation
Noise mitigation is a set of strategies to reduce noise pollution. The main areas of noise mitigation or abatement, are: transportation noise control, architectural design, and occupational noise control...
- Academic Programs in Acoustics
This page offers a partial list of academic institutions that offer significant exposure to the science of acoustics. Because acoustics is a broad, multi-disciplinary field, many institutions offer acoustics courses through various other departments, such as physics, architecture, or a particular...
External links