Where was most of Metallica's 1991 self-titled album, The Black Album, recorded?

Most of Metallica's 1991 self-titled album, The Black Album, was recorded at One on One Studios in Los Angeles.

The principal sessions began there on October 6, 1990, and continued through June 16, 1991. The studio was in the Los Angeles area and is also listed in the album’s recording credits as One on One in Los Angeles.

The band also spent about a week recording at Little Mountain Sound Studios in Vancouver, British Columbia. Additional overdubs and mixing took place at A&M Studios in Hollywood, so One on One was the main location rather than the only facility connected with the album.

The sessions became known for their demanding pace and the band’s arguments with producer Bob Rock. Rock wanted a more unified, live-feeling performance, which contributed to the album’s more direct and polished sound compared with earlier Metallica records.