# 331 4.1 Decibel

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The flashcards below were created by user shanamd2010 on FreezingBlue Flashcards.

1. Range of aduible sound
• 10^14 : 1
• rocket going off : wind in trees
2. to test hearing we transfer the audlibe sound ratio into
• a point system
• 0 - 140
3. 10^1
10^2
10^3
• 10
• 100
• 1000
4. 100,000,000
x 1,000,000 =
• 10^8 x 10^6 = 10^14
• 8 + 6 = 14
5. log2 =
.30103
6. ###### 10^1.? = 80
• 80 = 2x2x2x10
• = log2 x log2 x log2 x log10
• 10^.3 x 10^.3 x 10^.3 x 10^1
• .3 + .3 + .3 + 1 = 1.9
• 10^1.9 = 80
7. Hertz
Hz
8. Decibell
dB
9. Alexander Graham Bell
• teacher / scientist
• 1847 - 1922
• works with deaf
• work lead to telephone / aviation
• Scottich immigrant to Canada
• married a deaf women
• bffs with Helen Keller
• wanted to switch to the phonetic alphabet
• forbid signing
• thought the deaf and blind should not reproduce
10. decibel equation: dB spl
• dB SPL = 20 log (Pm / Pr)
• where:
• Pr = 20 uPa
11. Blaise Pascal
• French Scientist / Philoshopher
• 1623 - 1662
• Physicist / Mathematician
• Measurement of atmoshperic pressure
12. dB SPL tells you...
how far away from the reference you are
13. 0 dB SPL means
this is NOT 0, it means that you are at the reference
14. Pm = 8,000 uPa
dBspl = ?
• dBspl = 20 log(Pm/Pr) Pr = 20uPa
• = 20 log (8000/20)
• = 20 log (400) 400=2x2x100
• = 20 (2.6) 400=10^.3 x 10^.3 x 10^2
• dBspl = 52 400=10^2.6

### Card Set Information

 Author: shanamd2010 ID: 130645 Filename: 331 4.1 Decibel Updated: 2012-01-30 17:41:14 Tags: decibel Folders: Description: CDO 331 Show Answers:

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