Page 6 - Vibrations-2
P. 6
As you can see this is an inverse square law.
The Root Mean Square (RMS) is given by
=−1
1
2
= √ ∑
=0
Sound intensity level (SIL)
1
= ln ( ) = 10 log ( )
2 10
You use RMS when measuring noise. For acoustic sources,
Hand held device (decibel
meter) where the
measurements are performed
in dB, that way you avoid
having to calculate square
roots.
1
=−1 2
1
2
20log () = log 10 ( ∑ )
10
=0
5
