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Sound pressure level and sound intensity level

  1. Oct 15, 2007 #1
    Hi all.
    A very simple question: what is the difference between sound pressure level and sound intensity level?
    It seems to me that sound presssure level also measure the "energy" since it is p^2, which shall be related to energy...
    If it is so, it seems that sound pressure level shall be the same as sound intensity level, isn't it?
    Please help.
  2. jcsd
  3. Oct 15, 2007 #2


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    SPL is the actual pressure fluctuation that is measured. That is the pressure fluctuation due to the traveling wave. Sound intensity is a is the rate of flow of energy flow through a unit area as defined by

    [tex]\overrightarrow{I}=\frac{1}{T}\int_{0}^{T} p \overrightarrow{u} dt = \frac{1}{2}Re\left[p \overrightarrow{u}\right][/tex]
    Last edited: Oct 15, 2007
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