The ornamental design for an acousticbuildingelement, as shown and described.
FIG. 1 is a perspective view of a first embodiment of an acoustic building element showing my new design;
FIG. 2 is a front view of the acoustic building element of FIG. 1, the rear view, right side view and left side view being identical thereto;
FIG. 3 is a perspective view of a second embodiment of an acoustic building element showing my new design;
FIG. 4 is a front view of the acoustic building element of FIG. 4, the rear view, right side view and left side view being identical thereto;
FIG. 5 is a perspective view of a third embodiment of an acoustic building element showing my new design;
FIG. 6 is a front view of the acoustic building element of FIG. 5, the rear view, right side view and left side view being identical thereto; and,
FIG. 7 is a top view of the first embodiment of an acoustic building element shown in FIG. 1, the top views of the second embodiment shown in FIG. 3 and the third embodiment shown in FIG. 5 being identical thereto.
No drawing figures showing a bottom view are provided, as the bottoms of the acoustic building element are flat and include no surface ornamentation.