Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Total energy produced by sound source

  1. Feb 28, 2009 #1

    I have measurements of the sound intensity produced by a sound source for a given frequency (*). These measurements were taken on on a grid on an imaginary sphere around the source. From these measurements it is clear that the sound intensity is not equal in all directions.

    The measurements are calibrated in [tex]DB_{SPL}[/tex].

    The problem: how can I get an estimate of the total energy dissipated by the source?

    What I did so far is:
    -for each point I calculate the area of the sphere that is covered by the point.
    -I convert the DB values into intensity values: [tex]I = 10^{DB/10}[/tex].
    -multiplying the Intensities in each point with the area of covered by the point
    -summing all these numbers.
    -to get an absolute intensity value, I multiply this number with 10^-12 (the sound pressure level base for calculating Db values).
    -This number should give the number of WATTS. This should be multiplied with the duration the sound source is on.

    The questions:
    -So, is this correct?
    -Is there a quick way to calculate the energy dissipated for example using a simple model for a source?


    (*) The source produces more than 1 frequency of course. But let's start off easy.
  2. jcsd
  3. Feb 28, 2009 #2
    Last edited: Feb 28, 2009
  4. Mar 1, 2009 #3
    Thank you for the reply, but I knew about this site.

    The problem is that it just gives a way to calculate Intensity ( = W/M² or J/M²S) from Decibel. It does not give a way to calculate Energy (W*Time) for non-uniform distribution of W in space.

    So, that does not help me very much to solve my particular problem. But I agree that www.sengpielaudio.com is a top site.
  5. Mar 2, 2009 #4
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook