well, LH, I didn't quite read it that way, first of all I don't think Peggy and Ewan were goring any particular ox, it was a recorded interview, Joe Heaney is the one who didn't think Joan was 'authentic'. Not that they might not have agreed, though Ewan certainly went through some changes himself till he became the 'authentic Scotsman'! I just think it interesting that Heaney would hear whether some one was 'folk' or a 'folk song singer/stylist'. I don't think it was just the vibrato they were referring to, and this interview was 1964, so they would have played him some early traditional songs recorded by Joan, with little vibrato, I'd guess. Now, Buffy Saint-Marie anyone?