I don't see anything in Wikipedia about it, but (from this question) when I try to reproduce the equations in this 1933 paper, I get values 106 away from the values in the paper. When I reproduce this equation, for instance:
I get 5×10−11 bar
Likewise, it says:
Sound intensity and pressure are related by acoustic impedance of air Z0 = 400 N·s/m3.