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| Question 83004:  The loudness of sound is based on intensity level measured in decibels using a logarithmic scale and is relative to (a ratio of) the weakest sound the ear can hear.
 I need the formula for measuring sound and pick a specific sound (a jet's sound when taking off) give the decibels of the sound, and explain what this measurement means.
 Answer by ankor@dixie-net.com(22740)
      (Show Source): 
You can put this solution on YOUR website! The loudness of sound is based on intensity level measured in decibels using a logarithmic scale and is relative to (a ratio of) the weakest sound the ear can hear. I need the formula for measuring sound and pick a specific sound (a jet's sound when taking off) give the decibels of the sound, and explain what this measurement means.
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 The decibel formula for sound intensity:
 D = 10*log
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 Where Io = 10^-12 which is the threshold of hearing (usually, the reference)
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 The formula gives the decibel value of I, compared to Io
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 An algebra book that I have gives the sound intensity of a jet with afterburner as:
 8.3*10^2
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 Using the above formula where:
 Io = 10^-12
 I = 8.3*10^2
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 D = 10*log
  = 10*log  add the exponents here D = 10*log
  = 10*log  Find the log of 8.3(10^13) on a calculator
 D = 10 * 13.919
 D = 139.92 decibels
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 The ear has an incredible range the loudest sound that a person can hear without
 damage to his ear, is 1,000,000,000,000 times the softest sound he can hear.
 It's more convenient to use a logarithmic scale when dealing with big numbers
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 I (intensity) is actually the sound measured in watts per square meter
 Here's a few more:
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 Whisper: 5.2*10^-10
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 Heavy traffic: 8.5*10^-4
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 Jackhammer: 3.2*10^-3
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 The threshold of pain: 1*10^0
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 They don't give one for obscene rap music, the threshold of pain has to be close
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 Anyway, did this help you?
 
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