The ornamental design for an acousticpanel, as shown and described.
FIG. 1 is a front perspective view of an acoustic panel, showing my new design;
FIG. 2 is a rear perspective view thereof,
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a left-side elevation view thereof;
FIG. 6 is a right-side elevation view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The use of stippling indicates a contrasting appearance with adjacent portions.
The broken lines shown in the drawings depict the bounds of the claimed design, it being understood the broken lines form not part of the claimed design.