Homogeneity versus Frequency in a Reverberant Chamber

The acoustic field in a reverberant chamber is of diffuse nature in a given frequency band only if the modal density is sufficiently high, which is not the case at low frequencies. The cut-off frequency is given by the so-called Schroeder formula stating that it is proportional to the square root of the ratio reverberation time / chamber volume. This paper proposes to derive the proportionality factor from the homogeneity of the levels, defined as the ratio between the minima and the maxima at a given frequency, using some assumptions similar to those of the statistical energy approach. Formulation is presented and applied to the INTESPACE reverberant chamber for illustration.