While checking in at the Pearly Gates....
"Yes, St. Peter, I remember pushing the button on that air horn, and that REALLY seemed to anger that grizzly..... That's all I remember...."
Seriously, black bears will scare out of camp by just banging some pans together. That is, unless they have focussed on a clear source of food. You leave food out, and forget about trying to scare them away.....
No personal experience with grizzly's (and I prefer it that way!).