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Sound power question

  1. Aug 22, 2010 #1
    Hi Guys,

    I know that sound power can be measured in watts. For example a Jackhammer is around 120db which would produce a watt of electricity.

    My question is, if I wished to artificially create a sound at the same db would you have to put in as much energy?

    For example... if a rocket engine at 180db produced a potential of a million watts, if I wanted to artificially create this decibal volume would a million watts of energy have to be put in to it to generate it?

    Thanks guys!
     
  2. jcsd
  3. Aug 22, 2010 #2
    Yes, and more. You can't create sound with 100% efficiency, so you'll need more. The jackhammer makes heat and breaks rocks while it makes sound so it may require dozens or hundreds of watts to make one watt of sound.
     
  4. Aug 22, 2010 #3
    What if the sound is produced virtually? computer-generated and put through a speaker big enough to artificially create the sound power of 180db? would that be using more power output?

    To my mind, to do it the way I just put it wouldn't need a million watts or more to generate the sound power of 180db.
     
  5. Aug 22, 2010 #4

    cjl

    User Avatar

    No speakers are 100% efficient, so if you want to make a million watts of sound power, you need at least a million watts of input.
     
  6. Aug 22, 2010 #5
    Thanks very much for the information guys! very useful :)

    on a final note, in which way must things be 100% efficient?
     
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