Level at a new distance, then add levels
Line source 80 dB from 1 m to 4 m
Worked inputs. Not a measured place.
Worked example
Level at distance 2 73.9794 dB
Point: Lp2 = Lp1 - 20 log10(d2/d1). Line: Lp2 = Lp1 - 10 log10(d2/d1). Both distances stay in the selected unit. Ground reflection and air absorption are not added.
Tick position is the distance. Bar length is a drawing scale capped at 120 and is not the copied value. If the number you type is already dBA, the distance result stays in that weighting. This page does not turn dB into dBA.