You create a loud noise that can be easily heard by anybody within 1,000 ft. (no Perception check required). The noise can penetrate up to two feet of stone or six inches of iron. You can decide on the general sound of the noise, but it must be short and simple. For example a bell, a sword clashing, or a scream would all be possible, but a melody, multiple sounds of battle, or intelligible speech would not be possible.