The transmission loss achieved by a single isotropic partition can be estimated from its
weight per unit area, for each frequency, from the graph presented in Figure 10.20. The straight
portion of the curves is referred to as the "mass law" range because in this range the
transmission loss of the partition is proportional to its mass; that is, every doubling of the mass
per unit area of the partition results in a 6 dB increase in transmission loss.