[mitthrowaway2]

Of course, typical of the wonderful ambiguity of decibels, 0 dB is also usually defined as the quietest sound that the human ear can perceive.

https://en.wikipedia.org/wiki/Absolute_threshold_of_hearing

[ianburrell]

That's why important to give the scale. dBfs is full scale level, and db SPL is sound pressure level.

[rramadass]

Yep.

"Sound Power Level SWL", "Sound Pressure level SPL", and "Sound Intensity Level SIL" are different quantities which should not be confused. - https://sengpielaudio.com/calculator-soundpower.htm

A sound source produces sound power and this generates a sound pressure fluctuation in the air. Sound power is the distance independent cause of this, whereas sound pressure is the distance-dependent effect.

Sound pressure p is a "sound field quantity" and sound intensity I is a "sound energy quantity". In teachings these terms are not often separated sharply enough and sometimes are even set equal. But I ~ p2.