We claim the ornamental design for a speaker, as shown and described.
FIG. 1 is a perspective view of a speaker, showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left-side elevation view thereof;
FIG. 5 is a right-side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a perspective view thereof, shown in environmental use; and,
FIG. 9 is another perspective view thereof, shown in environmental use.
The broken lines in the figures illustrate the portions of the speaker and form no part of the claimed design.
The broken line showing of the coaster in FIGS. 8 and 9 is for the purpose of illustrating environmental subject matter that forms no part of the claimed design.