Sound Pressure Level ISPL) vs Distance

 

Sound is here the sound level, no matter if it is the sound pressure level or the sound intensity level.
 
Calculate the sound level L2 we know at the distance r2
Reference distance r1 
from sound source  
 m or ft		 Sound level L1
at reference distance r1 
 dBSPL
Search for L2
Another distance r2
from sound source  
 m or ft		 Sound level L2
at another distance r2
 dBSPL		 Sound level difference 
Δ L = L1 − L2
 dB
 
Calculate distance r2 where we know the sound level L2
Sound level L1 
at reference distance r1 
 dBSPL		 Reference distance r1 
from sound source  
 m or ft
Search for r2
Sound level L2
at another distance r2 
 dBSPL		 Another distance r2
from sound source  
 m or ft		 Difference of distance  
Δ r = r2 − r1
 m or ft