Metallica recorded additional overdubs and mixing for The Black Album at A&M Studios in Hollywood.
The album’s principal sessions took place at One on One Recording Studios in Los Angeles, but the production moved to other facilities as the record neared completion. A&M Studios provided the Hollywood setting for later overdubbing and mixing work.
This distinction matters because “recorded at” can refer either to the main tracking location or to the full collection of studios used during production. Metallica also spent about a week at Little Mountain Sound Studios in Vancouver.
The demanding process contributed to the album’s polished, weighty sound. Producer Bob Rock worked with the band through extensive revisions, while Randy Staub handled the original mix and George Marino mastered the finished recording.