Where was most of Metallica’s 1991 album recorded?

Most of Metallica’s 1991 album was recorded at One on One Recording Studios in Los Angeles.

The band began the main recording work at the Los Angeles facility in October 1990. The studio was in the North Hollywood area and became the principal setting for the album’s demanding sessions.

The project also involved about a week at Little Mountain Sound Studios in Vancouver, British Columbia. Additional overdubbing and mixing took place at A&M Studios in Hollywood, but One on One remains the studio most directly associated with the album.

The recording process was unusually intense. Producer Bob Rock pushed the musicians to record collaboratively and perform many takes, while the band pursued a more immediate, live-feeling sound. That difficult process was later documented in A Year and a Half in the Life of Metallica.