*2.3.4 Acoustic divergence* Adiv

ISO 9613-2 assumes any sound source as a point one. Then, it uses a spherical or quadratic divergence, as presented in Eq. (9).

$$L\_{p,r\_1} = L\_{p,r\_0} - 10\log\left(\frac{r\_1^2}{r\_0^2}\right) \tag{9}$$

Where:

*r0*: distance in meters from the source where its emission sound pressure levels were measured

*r1*: distance in meters from the source to the measuring point

*Lp,r0*: measured sound pressure level, at a distance r0 from the source *Lp,r1*: expected sound pressure level, at a distance r1 from the source
