Yep. Mr.Baer nailed it. Point his own rig at his head and then DEFY him to play at such levels. If that doesn't work, I'm sorry but you are just playing with and overgrown four year old jerk. He won't change. And you're not very smart if you go out and buy a 14 gigawatt amp to try and keep up. Try to work with him ONCE! TELL him the story of how you turned your amp off in practice the other day. See what his reaction is. IF he thinks it's YOUR fault, get to stepping. You don't need silly little boys like that. I don't care if he's 50 years old, if he acts like that he's a silly little spoiled rotten brat!