  We investigate shock wave effects upon the diffuse supernova neutrino
background using dynamic profiles taken from hydrodynamical simulations and
calculating the neutrino evolution in three flavors with the S-matrix
formalism. We show that the shock wave impact is significant and introduces
modifications of the relic fluxes by about $20 \%$ and of the associated event
rates at the level of $10-20 \%$. Such an effect is important since it is of
the same order as the rate variation introduced when different oscillation
scenarios (i.e. hierarchy or $\theta_{13}$) are considered. In addition, due to
the shock wave, the rates become less sensitive to collective effects, in the
inverted hierarchy and when $\sin^2 2 \theta_{13}$ is between the Chooz limit
and $10^{-5}$. We propose a simplified model to account for shock wave effects
in future predictions.
