structure of sound insulation wall

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 A perforated plate with air layer between the end face and the ceiling, even if the material has poor sound absorption function, the layout also has the function of sound absorption, such as perforated gypsum board, wood board, metal plate, slit sound absorbing brick and so on. This kind of sound absorption is called the cavity resonance sound absorption or Helmholtz (German physicist, von Helmholtz Ilermmann, 1821hz~1894hz) resonance sound absorption. The acoustic resonance absorption principle is similar to the thermos bottle, external space and internal cavity through the bottleneck link narrow, acoustic wave incident at the resonance frequency, the energy loss effect of intense resonance occurs between the air and the inner space of the neck. Helmholtz resonance sound absorption is characterized as long as the resonance frequency has a larger sound absorption coefficient.
Cavity resonance sound absorption is the center of the layout layout, there must be closed volume of the cavity, and through holes have certain depth and sound spatial connectivity, the sound absorption mechanism can be used to explain the Helmholtz resonator. When the depth of the hole T and the aperture D is much smaller than the acoustic wavelength, the elastic deformation of the air column in the hole is small and can be regarded as the mass block. Close the cavity volume ratio of V hole Jingda much, the whole system of similar spring oscillator. When the external incident frequency and natural frequency of Fo to f system usually air column hole in the neck because of resonance oscillation, the oscillation in the air column and neck side wall and the cost of energy conflict.






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Tags: sound insulation wall