Task: Explanation
Input (English): Farrokh "Freddie" Mercury (born Bulsara; 5 September 1946 – 24 November 1991) was a British singer, songwriter and record producer, known as the lead vocalist of the rock band Queen. He was known for his flamboyant stage persona and four-octave vocal range. Mercury wrote numerous hits for Queen, including "Bohemian Rhapsody", "Killer Queen", "Somebody to Love", "Don't Stop Me Now", "Crazy Little Thing Called Love", and "We Are the Champions". He led a solo career while performing with Queen, and occasionally served as a producer and guest musician for other artists. Question: Barcelona is the second solo album recorded by a singer known for his four-octave what? Answer: vocal range
Output (English):  He was known for his flamboyant stage persona and fouroctave vocal range.