I'm new to Rock Band (played Guitar Hero a fair bit though), and I'm having trouble activating star power consistently using vocals. My screaming is apparently not loud enough or something. I seem to have to whack the mic against the furniture (or my Wiimote) to get it to detect me trying to activate it, and even then it doesn't always work. In Guitar Hero, I can press a button to activate it, but that's apparently not the case in Rock Band.
Anyone have any bright ideas for a more foolproof method?