FIG. 1 is a perspective view of a first embodiment of a speaker box showing my new design; FIG. 2 is a top plan view thereof; FIG. 3 is a bottom plan view thereof; FIG. 4 is a left side elevational view thereof; FIG. 5 is a right side elevational view thereof; FIG. 6 is a front elevational view thereof; and FIG. 7 is a rear elevational view thereof. FIG. 8 is a perspective view of a second embodiment of a speaker box showing my new design; FIG. 9 is a top plan view thereof; FIG. 10 is a bottom plan view thereof; FIG. 11 is a left side elevational view thereof; FIG. 12 is a right side elevational view thereof; FIG. 13 is a front elevational view thereof; and FIG. 14 is a rear elevational view thereof. FIG. 15 is a perspective view of a third embodiment of a speaker box showing my new design; and FIG. 16 is a front elevational view thereof. The rest of views thereof is the same as those of the first embodiment. FIG. 17 is a perspective view of a fourth embodiment of a speaker box showing my new design; and, FIG. 18 is a front elevational view thereof. The rest of views thereof is the same as those of the second embodiment.