Sound Range of Hearing

Amplitude (pressure) range of hearing (humans)

• Threshold of audibility: 0.00002 N/m$^2$
• Threshold of feeling (or pain!): 200 N/m$^2$

Sound intensity range (humans)

• $I_0 = 10^{-12}$ W/m$^2$ (threshold of audibility)
• 1 W/m$^2$ (threshold of feeling)

The intensity ratio between the sounds that bring pain to our ears and the weakest sounds we can hear is more than $10^{12}$.