FIG. 1 is a front side perspective view of a wireless audio speaker, embodying my new design; FIG. 2 is a right side elevation view thereof; FIG. 3 is a left side elevation view thereof; FIG. 4 is a front elevation view thereof; FIG. 5 is a rear elevation view thereof; FIG. 6 is a top plan view thereof; and, FIG. 7 is a bottom plan view thereof.