When I was singing professionally, I sang mostly in bars and had to learn to not be upset when someone talked. But there is a limit. I remember one occasion when a man was singing along to every song I sang and decided he would join me in front of the mike. I asked him if he knew "If I Were a Carpenter," and when he replied "no," I said "Good, that's what I'm going to sing next." He and his little group left and the night continued on very well without him. Another occasion was when I was singing at a local bar and there was a woman sitting right next to me and she sang every song ... offkey. After a while, I leaned over and said "I'm flattered that you want to sing along with me, but would like it to be intune." That all may sound callous, however, these two individuals really were not very pleasant, they were not regular customers, they were barhopping, and they had no respect for, not only me, but for the patrons who had come to hear me. I realize this isn't your same situation, but rudeness is rudeness. If this person is a regular at your song circle, they are well aware of the protocol. I have become weary of "talking" over everything that happens in life. I think I would simply say "I'm sorry you were offended by me because it was not my intention." I think talking it over won't solve anything because his ego is too big and he probably won't get it. Of course, I don't know any of these people and my rhetoric may just be totally off kilter ... moonchild