The variance of the discrete frequency transmission function of a reverberant room.

This paper first shows experimentally that the distribution of modal spacings in a reverberation room is well modeled by the Rayleigh or Wigner distribution. Since the Rayleigh or Wigner distribution is a good approximation to the Gaussian orthogonal ensemble (GOE) distribution, this paper confirms the current wisdom that the GOE distribution is a good model for the distribution of modal spacings. Next this paper gives the technical arguments that the author used successfully to support the pragmatic arguments of Baade and the Air-conditioning and Refrigeration Institute of USA for retention of the pure tone qualification procedure and to modify a constant in the International Standard ISO 3741:1999(E) for measurement of sound power in a reverberation room.