I m pretty sure Yma could have gone higher But she did hold the highest Note I believe but only by a half step since the highest by opera singers was C7 Her range is in fact 4 octaves Some singers inaccurately exploit their range Mariah s is less than five octaves and as is Yma s Yma s lowest note is in the 2nd octave I forgot what note it is but it would have to be C2 for her range to be 5 octaves which it is nt However they can stay since this category seems useless and not very well varified And Misia s highest notes are like G6 s or A6 s