Calculator
Decibel Distance Calculator — Train Horn Loudness at Any Distance
How loud is a 150 dB horn at 100 feet? At a quarter mile? Enter source SPL and distance — get the perceived decibel level using inverse-square-law.
150dB
The rated output on the horn's spec sheet
90160
100ft
How far away the listener is
101000
At 100 ft, you'll hear
~130dB
Roughly the same as: Jackhammer (close) (130 dB)
Ring chart
Rings show how dB drops with distance around the source. The dashed circle marks your chosen distance.
Where it sits on the scale
130 dB
30 dB · whisper100 · subway120 · jet takeoff160 dB · gunshot
The OSHA permanent damage threshold starts at 85 dB with long exposure and drops to seconds at 110+ dB.
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