The ornamental design for a portablespeaker, as shown and described.
FIG. 1 is a front view of a portable speaker showing our new design;
FIG. 2 is a rear view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top view thereof; and,
FIG. 6 is a bottom view thereof.
The greyscale shading in FIGS. 1-6 is provided solely for the purposes of showing surface contours, to assist in visually differentiating elements of the design from each other and to designate the claimed design from unclaimed portions of the claimed design as noted below. Color forms no part of the claimed design. The dashed broken lines shown in FIGS. 1-4 and 6, and the lightened areas shown within the dashed broken lines in FIGS. 1-4, are included for the purpose of illustrating portions of the Portable Speaker that form no part of the claim.