How does one physically measure the decibel level of sound?
In: 3
You measure the changes in air pressure.
dB = 10 log (I/I0) where I is the intensity of the sound you’re trying to measure, and I0 is the
Intensity of sound is I = 2 π^2 f^2 A^2 ρ c
f is the frequency (how often the wave oscillates)
A is the amplitude (how far from ambient pressure the wave oscillates)
ρ is the density of the medium (usually air)
c is the speed of sound in that medium
I0 is simply defined as 10^-12 Watts/m^2 which is the lower threshold of human hearing.
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