Calculating Noise Level at various distances from the source
The equation is:
r0 is the noise level at distance L0 & L is the level at r
Therefore if you know the noise level at 3 feet (or any distance) you can calculate the noise level at other distances with this equation.
Suppose you know that the blower is at a level of 95 dbA at 3 feet and you want to know what it is at 10 feet.
This equation assumes that there are no major reflecting surfaces nearby. This equation is known as the “inverse square law field”.