Loudness

Humans can hear sounds about 0.00002pa frequenciesof 4kHz.

         20 log(P / P0)[dB]

          P  : dB [μPa]
          P0 : 20[μPa]

            Daily sound pressure levels

Sound pressure [Pa] Sound pressure levels [dB]
Minimum audible pressure
0.00002 0
Whisper (1m)
Rustling of leaves
0.0002 20
Conversation (1m)
Ride sound
0.02 60
Crowded town
Inside an air plane
0.2 80
An underground railway
Dogs roar
0.5 90
Jet engine (50m)
20 120