Which Los Angeles studio was the main recording site for Metallica's 1991 album Metallica?

One on One Recording Studios in Los Angeles was the main recording site for Metallica's 1991 album Metallica.

The band began recording there in October 1990. The sessions lasted for much of the following eight months and involved extensive work with producer Bob Rock, whose methods encouraged the musicians to perform more collectively in the studio.

Metallica also spent about a week at Little Mountain Sound Studios in Vancouver, British Columbia. Final overdubs and mixing were completed over four weeks at A&M Studios in Hollywood during June and July 1991. These additional locations are why the album is associated with more than one studio.

One on One therefore refers to the principal recording venue, not every facility used during production. The album's studio work ended on June 16, 1991, before its August release.