Top 10 Singers with a 4 Octave Vocal Range

4 Octaves means neither more nor less than 4 octaves.
This vocal range is something remarkable.
Because they all have the same vocal range, I ranked them by vocal skills.
The items in this list have been selected by the author of the list for you to vote and comment on.
The Top Ten
1 Freddie Mercury Freddie Mercury (born Farrokh Bulsara, 5th September 1946 - 24th November 1991) was a Zanzibari-born British singer of Indian descent, songwriter and record producer, known as the lead vocalist and songwriter of the British rock band Queen. He also became known for his flamboyant stage persona and four-octave vocal range. Before he became a singer he has been in 3 other bands (Ibex, Sour Milk Sea, and The Hectics). He died on November 24, 1991 from bronchopneumonia as a result from HIV/AIDS

I don't have to think about this.

Him and Ian Gillan are my favourites of this list.

Amazing singing skills.

Almost 5.

2 Geoff Tate Geoff Tate is a German-born American singer and musician who rose to fame in the 1980s with the progressive metal band Queensrÿche.
3 Ian Gillan Ian Gillan is an English singer and songwriter. He originally found success as the lead singer and lyricist for Deep Purple, and the original singer on the rock opera concept album Jesus Christ Superstar by Andrew Lloyd Webber, where Gillan had the leading role (Jesus Christ).
4 Jon Oliva John Nicholas Oliva, known as Jon Oliva, is an American composer, multi-instrumentalist and singer. Co-founder of the metal band Savatage and the rock opera Trans-Siberian Orchestra. He's got a real 4 octave range, able to morph the sound of his voice to any style, from John Lennon and Freddie Mercury, ...read more.
5 Maynard James Keenan Maynard James Keenan, often referred to by his initials MJK, is an American musician, record producer, winemaker, and actor, best known as the vocalist for Grammy Award-winning progressive metal band Tool. He also is the singer of A Perfect Circle and Puscifer bands that vary in style.
6 Tom Araya Tomás Enrique "Tom" Araya Díaz is a Chilean American musician, best known as the bassist and vocalist of the American thrash metal band Slayer.
7 Daniel Heiman Daniel Heiman (born June 11, 1974) is a Swedish power metal singer. He is most famous for his time in Lost Horizon. After leaving Lost Horizon, he recorded an album with the band Crystal Eyes, and later founded the band Heed.
8 Kai Hansen Kai Michael Hansen is a heavy metal guitarist and vocalist. Hansen is the founder, lead guitarist, and vocalist of power metal band Gamma Ray. He is also the co-founder and former member of German metal band Helloween.
9 Glenn Hughes Glenn Hughes is an English rock bassist and vocalist, best known as a member of Deep Purple and the rock pioneers Trapeze, and his solo career. Hughes was inducted into the Rock and Roll Hall of Fame as a member of Deep Purple. He is acclaimed for his wide vocal range.
10 Brendon Urie Brendon Boyd Urie, more commonly known as Brendon Urie, was born April 12, 1987, in St. George, Utah. He is an American singer, songwriter, musician and multi-instrumentalist. He is best own as the lead singer of the American pop-rock band Panic! At The Disco. He is the only original remaining member. Urie is currently playing Charlie Price in Kinky Boots on Broadway. Brendon is also known for singing "I Write Sins Not Tragedies," the band's first hit song, in 2005. He also sings "Victorius," "Death of a Batchelor," and "This is Gospel." Brendon also has a very unique voice. He has a D2-C7, 4-octive range. He shows this in "Death of a Batcheor" and "The End of All Things."

He deserves to be higher on this list.