  The presence of resonances modifies the passage of light or of electrons
through a disordered medium. We generalize random matrix theory to account for
this effect. Using supersymmetry, we calculate analytically the mean density of
states, and the effective Lagrangean of the generating functional for the
two-point function. We show that the diffusion constant scales with the
effective mean level spacing. The latter exhibits a resonance dip. These facts
allow us to interpret experimental results on light scattering for different
concentrations of resonant scatterers.
