Longitudinal and shear wave velocities have been measured at 2 kHz and 200 kHz. The measurements were made in a granite as a continuous function of partial water saturation and effective pressure. The pore space of the granite consists of microcracks. The low frequency results compare favorably to the low frequency limit of poroelastic theory. Poroelastic theory assumes that the pore space is connected. On the other hand, the ultrasonic results are better described by effective medium scattering theories: the self-consistent and the average T-matrix approximations. Each of these theories assume that the microcracks are not connected.