This paper investigates how the regime (quasi-static, transient, out of equilibrium) of the phenomena occurring at pores scale determine the nature of the (non)-local effect-in time and/or space-involved in the macroscopic behavior of a porous medium. The study focuses on sound propagation examining-through the homogenization method of periodic media-situations of single porosity, Rayleigh scattering and double porosity. Non-locality effects reveals the loss of a perfect quasi-static equilibrium free of volume loading at the local scale. The non-locality in time is due to phenomena in transient regime at the ERV scale, while non-locality in space is due to the non-homogeneity in space of the macrofields. The generality of the arguments lead to infer that the conclusions about non-locality versus pores scale regime, could be extended to other physical phenomena in heterogeneous media.