Thank you for those comments.
I agree that there are numerous factors that can affect the calculation for instance the vertical mudstone escarpment 12 meters in front of the speakers.
Most equipment these days seems to quote a db value for either a meter or for the user.
What I would like to...
If I am using a brush cutter creating 98db at ear (manufacturers claim) and I can still hear music from 30m away what would the db be at the source of the music.
I was wearing ear defenders but presume that they would work equally on both sources of noise.
I am lead to believe that the...