Overdubs and mixing for Metallica's The Black Album were completed at A&M Studios in Hollywood.
The album's principal recording took place at One on One Recording Studios in Los Angeles, but the production moved between several facilities. Metallica also worked for about a week at Little Mountain Sound Studios in Vancouver, British Columbia, before returning to Los Angeles for additional work.
A&M Studios therefore describes the finishing stage rather than the main recording location. This distinction explains why different accounts may name One on One, Little Mountain Sound, or A&M Studios when discussing where the album was made. Each location played a different part in the process.
Producer Bob Rock oversaw the sessions, which ran from October 1990 through June 1991. The completed album was released by Elektra Records on August 12, 1991, and its polished, powerful sound helped distinguish it from Metallica's earlier thrash-metal recordings.