Unfortunately it seems that Bono is loosing some of his range. Last time I saw U2 in concert (summer 2005) he couldn't reach some of the high notes and hold them as he once could.
Freddie Mercury possessed a remarkably light voice, capable of producing not only very high sounds but low sounds as well. If we were to classify him according to the classic standards he would be a light tenor or a lyric tenor. He had a most enviable vocal extension, with an outstanding range of three octaves and a major sixth, including his falsetto singing (F1-D5).
Since falsetto is not a part of a singer's real range, his real full-voiced range was three octaves (F1- F4).
But Freddie was actually a baritone. His lowest range, (below C2), it's not a tenor tessitura. He was a light baritone, who was actually singing in tenor's range. His passagio zone was, in fact, more similar to tenor's than a baritone's.
