In this ideal geometry, the reverberated sound field is in the assumptions of a diffuse field. Thus, as expected, the TCR and the MD code are quite appropriate to model the sound field. In addition the SPPS code gives also relevant results. Both TCR/MD/SPPS code gives similar results in term of sound level. The only problem is observe when the receiver is at the exact location of the source, where an artefact (i.e. a singularity) is observed for the TCR/MD codes, since the direct field cannot be calculated (distance source-receiver is equal to 0 in this situation). The two versions of the diffusion model (MD_Comsol (2010), i.e. the old one and the MD_Octave (2018), i.e. the recent one) gives similar results.

Here again, for an uniform absorption of 0.1, since the reverberated sound field is in the full assumptions of a diffuse field, the TCR results should be the expected values. Both SPPS and MD codes gives similar values in comparison with TCR results. However, one can observe a small overestimation of the RT30 using the old version of the MD code (MD_Comsol). Here again, we have also an artefact for the MD code (Octave) at the source location. For an absorption of 0.5, we are no more in the full assumptions of a diffuse field (absorption becomes too large). It explains why the MD/SPPS codes gives slightly different results than the TCR code, that is an expected result. Here again, the MD_Octave code give better result than the MD_Comsol ones. In summary, in this kind of geometry, the MD and SPPS codes are very relevant, going beyond the limits of the TCR model when absorption becomes larger.