Would it be possible to base the intensity of the shout on how long you've held down the button? Then you would be able to tap the button and whisper to see if a zombie is on the other side of a door, or shout loud enough to only alert zombies in the house your raiding, or full out yell clear the zombies out of an area. Along with this could come an indicator showing the radius of your shout as you charge it up, or the perimeter. The radius should probably oscillate from min to max as you hold the button for those of us that can be indecisive or just get excited and accidentally push the wrong button.