she barely has a octave range it's not impossible to have an octave range which is currently the guiness world record for largest vocal range held by georgia brown g g is her range but i've only heard g since her g is actually able to be heard and sounds more like a b or b nicola sedda actually has the largest vocal range that i know of which i only remember his highest as a the fact is that mariah has only displayed a range of bb g which is very close to a full octaves bb has only been displayed in an interview and g has been hit twice in live performances of emotions and seemed fairly easily done besides bb she has hit c numerous times emotions my all you and i live performance and other songs have c as their lovest besides g f is her highest in the studio version of all in your mind