Time-resolved diffraction patterns down to a sub-nanosecond scale obtained with a high-resolution diffractometer for high-energies X-rays on ultrasonically excited samples are presented. The time resolution gives direct insight into the purity of the excited sound waves and reveals the density of states for the lattice parameter at any point of time in a MHz oscillation period. The combination of the time resolution with the momentum transfer Q accessible by the high-energy diffractometer gives access to a unique regime in (Q,t) space.