Abstract: An exact sound power emission formula of a simple source in a reverberation chamber is derived from normal mode theory as a function of its position in the room, and important properties of the emission are found from simple analyses.
For example, the average emission of the source in the room' is not' equal to the free-space emission but greater, on the contrary to the common notion. A smooth statistical formula is also derived for the variation of average sound power in an axial direction, which holds even at low frequency at which the wave length approaches th mean free path in the room.
The sound power is found to have numerous peaks in the room forming a three-dimensional lattice structure with high power barriers around the boundary walls. The space factor in- an axial direction is essentially exact, but the general formula of power emission formed with the product of space factors in three axial directions might have some error. Numerical examples are presented to check this. The variability of sound power emission in reverberation chambers should be taken into account in the application and measurement of sound sources.