Sound Intensity and Threshold of hearing

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SUMMARY

The discussion centers on the equation β = 10log(I1/I2), where I1 typically represents the threshold of hearing at 1.0x10^-12 W/m². Participants clarify that I1 may not always be the threshold of hearing when measuring sound intensity for purposes other than human perception. The reference intensity for zero dB is established as 1 pico-Watt/m². Understanding the context of sound intensity measurement is crucial for accurate interpretation of this equation.

PREREQUISITES
  • Understanding of sound intensity and decibel scale
  • Familiarity with the equation β = 10log(I1/I2)
  • Knowledge of threshold of hearing (1.0x10^-12 W/m²)
  • Basic concepts of sound measurement and perception
NEXT STEPS
  • Research the applications of sound intensity measurements in various fields
  • Explore the differences between human hearing thresholds and other reference levels
  • Learn about the effects of frequency on sound perception
  • Investigate advanced sound intensity equations and their practical implications
USEFUL FOR

Acoustics researchers, audio engineers, and anyone interested in the scientific principles of sound measurement and human hearing thresholds.

gomess
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My textbook says that in the equation β= 10log(I1/I2), I1 in most cases is the threshold of hearing (1.0x10^-12). Just out of curiosity, when is I1 not the threshold of hearing?
 
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the reference intensity for zero dB, is 1 pico-Watt/m^2 . I can't hear such faint sounds anymore, especially at the edges of my frequency range. I used to be able to hear 1/8 picoWatt/m^2 ... that's -9 dB ... at 880 Hz.
 
gomess said:
My textbook says that in the equation β= 10log(I1/I2), I1 in most cases is the threshold of hearing (1.0x10^-12). Just out of curiosity, when is I1 not the threshold of hearing?

Well sound intensity is the measure of a ratio of two sound intensities, when we are discussing the sound intensity experienced by people, then it is useful to set this 'reference' level at the average threshold of human hearing. In any situation when you are not concerned with sound intensity as experienced by people, you might choose a different reference level, it would depend on what you wanted to measure.
 
Oh okay, i see that makes more sense. I was always wondering why we placed that value as I1, there seemed to be no explanation from my book, it simply stated to do so
 

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