Celtic Soul, I am not saying that vocal range runs one octave per catagory, thats absurd. There is a persistant myth that Mariah Carey can sing over six (some say seven) octaves. Not even Bobby McFerrin can do that, and he is ten times the musician that Mariah Carey is.
I think that the exaggerations of her being able to sing over six octaves are an attempt to give her legitimacy. I have music students who mouth this claim, and cannot even define what an octave is.
Normally I love blarney, but this isn't funny anymore.