Soundproofing
In contrast to sound insulation , sound attenuation is understood to be the hindrance of sound propagation through the absorption of airborne sound . With this sound absorption , the sound energy is converted into inaudible waves of vibration energy , mostly turbulence, and thus destroyed. Accordingly, the reflection of the sound at the interface , e.g. on walls, is reduced.
Sound attenuation or sound absorption is a feature of room acoustics : sound-absorbing components are used to specifically improve the acoustic properties of a room (e.g. the reverberation time ). Sound absorbing materials are building materials in which the sound propagation is subject to strong damping caused by sound dissipation .
The physical mechanisms of sound attenuation take place in the immediate vicinity of interfaces :
- viscous friction in the hydrodynamic boundary layer ,
- In the thermal boundary layer of the fluid , the thermal change of state during the sound process is no longer loss-free due to the heat transport from and to the wall, i.e. H. not isentropic or not adiabatic , while this is the case at a greater distance from the wall.
The effect of the mechanisms depends on a. on the size of the interface (surface). Airborne sound is absorbed particularly efficiently by porous materials with open pores that have a large internal surface and depth.
Differentiation from sound insulation
Sound insulation refers to the hindrance of the propagation of airborne or structure-borne sound into adjacent rooms by reflecting the propagating sound at individual points of discontinuity and is characterized by the sound reduction index R in dB .
Sound absorption and sound insulation are the fundamentals of building acoustics .
See also
Web links
- University of Oldenburg - Noise Abatement, Soundproofing and Soundproofing (PDF file; 379 kB) Retrieved on May 24, 2013.