Output of a Sound Source in a Reverberation Chamber and Other Reflecting Environments

It is important to know the output of a source as a function of position in a reverberation chamber. Expressions are given for the sound power output of simple monopole and dipole sources as functions of source position in various reflecting environments. They are obtained by the use of the method of images and a general formula due to Rayleigh for the output of a number of simple sources. The cases of a dipole source near a reflecting plane and a simple source near a reflecting edge and corner are treated, and the effect of the band width of the source is considered. The results apply when the reflectors enclose the source, as in a reverberation chamber, unless the distance in wavelengths between parallel walls is small and the absorption in the enclosure is low. Some experimental data are given, and the reverberation chamber method of measuring the power output of sources is discussed. In the general case of an extended source emitting nonspherical waves near reflecting surfaces, it may be more convenient to find the variation of power output with position by experiment than by calculation.