Threshold of Hearing
The minimum sound pressure level or intensity audible to a healthy human ear at 1000 Hz.
Governing formula
I0 = 10⁻¹² W/m² (0 dB SPL, P0 = 20 µPa)
SI unit
W/m² (0 dB)
In depth
Serves as the universal standard reference point $I_0$ for decibel acoustic level calculations.
Examples in the real world
The faint sound of a mosquito buzzing several meters away in a silent room.