The Big Three Christmas carols are usually sung in G major – Once in Royal David’s City, O Come All Ye/You Faithful, and Hark the Herald Angels Sing. At one of Vox Cape Town’s Nine Lessons and Carols services last week, I sang them all in A flat major. Everybody else sang in G major even if they did not know they were doing so. My voice was not a semitone out (I trust!); I was in my own universe of A flat major because that is what I heard. Top F, the highest note the tunes reach, is at the edge of my range requiring extra vocal and diaphragmatic effort. I felt that extra effort, even though in the real world i was singing top E, a semitone lower, and therefore more comfortable. Why did my vocal apparatus which was singing E make me feel that I was singing F? Presumably the altered brain overrode the muscles of the respiratory system’s upward messages.