FACTOID # 4: Just 1% of the houses in Nevada were built before 1939.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Soundproofing

Soundproofing is any means of to reducing the intensity of sound with respect to a specified source and receptor. There are several basic approaches to reducing sound: increasing the distance between source and receiver, using noise barriers to block or absorb the energy of the sound waves, using damping structures such as sound baffles, or using active antinoise sound generators. Noise barrier earth berm along Highway 12, Sonoma County, California A noise barrier is an exterior structure, normally made of masonry or earth, designed to protect sensitive land uses from noise pollution. ... A sound baffle is a construction or device which reduces the intensity of airborne sound. ... Active noise control (also known as noise cancellation or antinoise) is a method for preventing unwanted sound. ...


Soundproofing affects sound in two different ways: noise reduction and noise absorption. Noise reduction simply blocks the passage of sound waves through the use of distance and intervening objects in the sound path. Noise absorption, on the other hand, operates by transforming the sound wave. Noise absorption involves suppressing echoes, reverberation, resonance and reflection. The damping characteristics of the materials it is made out of are important in noise absorption. In audio signal processing and acoustics, an echo (plural echoes) is a reflection of sound, arriving at the listener some time after the direct sound. ... When sound is produced in an enclosed space multiple reflections build up and blend together creating reverberation or reverb. ... The Tacoma Narrows Bridge (shown twisting) in Washington collapsed spectacularly, under moderate wind, in part because of resonance. ... Spheres reflecting the floor and each other. ...

Contents


Distance

The use of distance to dissipate sound is straightforward. The energy density of sound waves decrease as they spread out, so that increasing the distance between the receiver and source results in a progressively lesser intensity of sound at the receiver. In a normal three dimensional setting, the intensity of sound waves will be attenuated according to the inverse square of the distance from the source. Using mass to absorb sound is also quite straightforward, with part of the sound energy being used to vibrate the mass of the intervening object, rather than being transmitted.


Damping

Damping is the process by which sonic vibrations are converted into heat. This can be achieved in several ways. For example, use of a material such as lead that is both heavy and soft, with the softness allowing it to damp the noise rather than allowing transmission. Making a sound wave transfer through different layers of material with different densities also assists in noise damping. This is the reason why open-celled foam is a good sound damper; the sound waves are forced to travel through multiple foam cells and their cell walls as sound travels through the foam medium. Improperly done, however, structural compliance can make things worse, such as the string holding chimes help them ring by isolating the vibration instead of damping it. Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations. ... This article is about the chemical element. ... Foam The most general definition of foam is a substance that is formed by trapping many gas bubbles in a liquid or solid. ... Compliance can mean: In mechanical science, the inverse of stiffness (see stiffness). ...


Noise cancellation

Noise cancellation generators for active noise control are a relatively modern innovation. A microphone is used to pick up the sound that is then analyzed by a computer; then, sound waves 180 degrees out-of-phase are output through a speaker, causing destructive interference and cancelling much of the noise. Active noise control (also known as noise cancellation, active noise reduction (ANR) or antinoise) is a method for preventing unwanted sound. ... Interference of two circular waves - Wavelength (decreasing bottom to top) and Wave centers distance (increasing to the right). ...


Noise barriers as exterior soundproofing

main article: Noise barrier

Since the early 1970s it has become common practice in the United States (followed later by many other industrialized countries) to engineer noise barriers along major highways to protect adjacent residents from intruding roadway noise. The technology exists to predict accurately the optimum geometry for the noise barrier design. Noise barriers may be constructed of masonry, earth or a combination thereof. One of the earliest noise barrier designs was in Arlington, Virginia adjacent to Interstate 66, stemming from interests expressed by the Arlington Coalition on Transportation. Possibly the earliest scientifically designed and published noise barrier construction was in Los Altos, California in 1970. Noise barrier earth berm along Highway 12, Sonoma County, California A noise barrier is an exterior structure, normally made of masonry or earth, designed to protect sensitive land uses from noise pollution. ... Noise barrier earth berm along Highway 12, Sonoma County, California A noise barrier is an exterior structure, normally made of masonry or earth, designed to protect sensitive land uses from noise pollution. ... Noise barrier earth berm along Highway 12, Sonoma County, California A noise barrier is an exterior structure, normally made of masonry or earth, designed to protect sensitive land uses from noise pollution. ... Roadway noise is the most prevalent form of environmental noise Roadway noise is the collective sound energy emanating from motor vehicles. ... A brick wall built using the Flemish Bond Masonry is the building of structures from individual units laid in and bound together by mortar. ... Arlington County is a county located in the U.S. state of Virginia (which calls itself a commonwealth), directly across the Potomac River from Washington, DC. By an act of Congress July 9, 1846, the area south of the Potomac was returned to Virginia effective in 1847 As of 2000... Interstate 66 is an interstate highway in the eastern United States. ... The Arlington Coalition on Transportation (ACT) is a citizens group formed to oppose the construction of Interstate 66 through Arlington, Virginia. ... Los Altos (IPA: ) is a city at the southern end of the San Francisco Peninsula (part of the Silicon Valley). ...


See also


  Results from FactBites:
 
Soundproofing - Wikipedia, the free encyclopedia (494 words)
Sound proofing is any mechanism used to reduce the conduction of sound through a barrier or into a soundproofed chamber.
There are several different basic approaches to reducing sound: increasing space in which the sound dissipates, using massive barriers to absorb the energy of the sound waves, using dampening structures such as sound baffles, or using active antinoise sound generators.
The energy density of sound waves decrease as they spread out, so increasing the distance between the soundproofed space and the source of noise will result in a smaller amount of sound reaching it.
SOUNDPROOFING YOUR BATHROOM (471 words)
Now granted, we don't get a lot of calls for bathroom soundproofing, however, there are those of you out there who would rather not hear or deal with (invasive) bathroom noise, especially while trying to sleep.
Soundproofing a bathroom is relatively easy due to the fact that it is not really feasible to float walls or ceilings, when bathroom space is so precious.
You now have a state of the art soundproofed bathroom, and will now be the envy of all your neighbors.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m