# Sound Growth

- The growth of sound in the room is described by:
- where
- Π = rate at which sound is being produced [W]
*A*= sound absorption of the room [sabin]*c*= speed of sound [ms^{-1}]- ρ
_{0}= density of air [kgm^{-3}] *V*= volume of room [m^{3}]- After an infinite length of time the pressure in the room will be:

- Note that using the above equation and knowing the sound power input to a room and the average pressure distribution over the room it is possible to calculate the absorption in sabin. If the area of the absorptive material is known it is possible from this to calculate the absorption coefficient of the material.

**See also: **Absorption Coefficient.

**Subjects: ** Audio