At which recording studio did Metallica primarily record its 1991 album Metallica?

Metallica primarily recorded its 1991 album Metallica at One on One Recording Studios in Los Angeles.

The sessions began in October 1990 and continued through June 1991. The band also spent about a week at Little Mountain Sound Studios in Vancouver, while additional overdubbing and mixing took place at A&M Studios in Hollywood.

One on One became the main setting for a difficult but important production period. Producer Bob Rock encouraged the musicians to work together as a band rather than recording every part separately, and the group performed many takes while searching for the right feel.

The studio is sometimes mixed up with Sweet Silence Studios in Copenhagen, where Metallica recorded Master of Puppets, or The Plant in Sausalito, where the band later recorded Load. Those were different albums and different sessions.