A sound absorption system

The sound absorption device comprises a multilayer structure (10) through a plurality of channels (1) forming a porous network and making the device permeable in its thickness (e). These channels (1) have section changes and result from a superposition of conduits (2) formed in the respective layers. The multilayer structure comprises at least two superposed layers having the same order of magnitude of thickness, the thicknesses of the two layers being defined by the distance measured between two discontinuities (3) successive said porous network. Delay section or transitions in the stack of elementary layers (11, 12, 13, 14, 15, 16, 17, 18, 19) provide a channel geometry which improves the sound absorption with respect to a homogeneous stack ( stacking phase) of elementary layers. This helps to dissipate the acoustic fields in oblique.