Who has the highest vocal range for a man?

mike matijevic from steelheart has been said to have the highest male vocal range, spanning close to 7 octaves. steelheart is a late 80's early 90's hair band, who unfortunately was talent that faded due to early grunge rise. steelheart recorded and released 3 albums, 1 in which was only released in Canada. matijevic also sang the vocals for movie star mark walhberg in the hit movie 'Rockstar", and played a cameo appearance in the movie as well. 1 of steelheart's best and widely known songs is ''i'll never let you go'', debuting in 1994.