The effect of varying the explosive sensitivity for a heterogeneous explosive formed of a packed bed of glass beads impregnated with liquid nitromethane (NM) sensitized with diethylenetriamine (DETA) is investigated. The changes in the dependence of critical charge diameter on bead size is investigated at concentrations of 5%, 10%, and 15% DETA over a range of bead diameters from 66/zm to 2.4 mm. Additional measurements are also performed on the critical diameter of the homogeneous liquid explosive itself. Three regions of behavior are identified for the bead-liquid explosive mixture. For bead sizes above approximately 1.5 ram, the critical diameter increases drastically as the amount of DETA is reduced from 15% to 10% and 5%. For bead sizes below approximately 1 mm, the critical diameter is nearly unchanged at concentrations of 10% and 15%. Between 1 and 1.5 mm, a region where the critical diameter increases sharply is found and detonation failure was observed in charge diameters of up to 60.5 mm. This transition region between the two others is found to be wider at lower DETA concentrations. This supports the previous proposition of two distinct mechanisms of detonation propagation which depend on the bead size: propagation through the pores of the media and propagation through the medium material itself.