Sophocleese Here's the view from the other side of the "I wish the guitarists would shut up" fence. When I go to a song circle I have not only learned the words to the songs I would like to do but I know exactly what keys I intend to perform them in. Singers should have enough respect for the flow of the music not to have play hunt for the key i.e. sotto voce humming the tune looking for the extreme highs and lows to see if they can handle them. Meanwhile the rest of the group sits feeling the energy dissipate. If you don't have access to an instrument to determine a comfortable starting pitch (at home where you're learning the song) at least ask one of the instrumentalists what key you were in at the end of your first presentation of the song. Remember it and ask someone to give you that pitch or chord the next time you do that song. This signals your listeners that you are ready to sing and that you are no wasting their time.

Michael