Sound Propagation in a Reverberation Chamber

The laboratory reproducibility of sound absorption measurements in reverberation chambers is still unsatisfactory [1]. The main requirement for measuring the absorption coefficient in a reverberation chamber is a diffuse sound field. Annex A of ISO 354 [2] states that the sound field in the chamber becomes more diffuse with an increasing amount of diffusers. The ideal amount of diffusers is reached, when the measured mean sound absorption coefficient in the frequency range from 500 Hz to 5000 Hz approaches a maximum value and remains constant with an increasing number of diffusers. Although this procedure is very common, a lot of different approaches for investigating the diffusivity of the sound field exist. Some of the approaches are described briefly in the following paragraphs.