Which Los Angeles studio was the main recording location for Metallica's The Black Album?

One on One Recording Studios in Los Angeles was the main recording location for Metallica's The Black Album.

The band recorded the album there during sessions that began in October 1990 and continued into 1991. One on One was a prominent Los Angeles facility, and Metallica used it for the core recording work that shaped the album's polished but forceful sound.

The group also spent about a week at Little Mountain Sound Studios in Vancouver, British Columbia. Additional overdubs and mixing took place at A&M Studios in Hollywood, so the album was not made entirely at one address.

The principal studio is sometimes confused with the album's other production locations or with the band's rehearsal spaces. Recording data also identifies the project as spanning October 6, 1990, to June 16, 1991, reflecting its extended development.