is the self-titled fifth studio album by American heavy metal
. Released on August 12, 1991, by Elektra Records
, it is commonly referred to as The Black Album
because of its packaging design. Its recording took place at One on One Studios
in Los Angeles over an eight-month span that frequently found Metallica at odds with their new producer Bob Rock
. The album marked a change in the band's music from the thrash metal
style of their previous four albums to a slower, heavier, and more refined sound.