Decibel Scale
A logarithmic scale used to express sound intensity or sound pressure level relative to a reference threshold.
Governing formula
β = 10 log10(I / I0), I0 = 10⁻¹² W/m²
SI unit
dB
In depth
Because human perception of sound loudness is logarithmic, every 10 dB increase represents a tenfold increase in physical sound intensity.
Examples in the real world
Normal conversation measured at ~60 dB ($10^{-6} W/m^2$), while prolonged exposure above 85 dB causes hearing damage.