At which Los Angeles studio did Metallica record the main sessions for The Black Album?

Metallica recorded the main sessions for The Black Album at One on One Recording Studios in Los Angeles.

The sessions ran from October 6, 1990, to June 16, 1991, and the album's recording is described as taking place at One on One over an eight-month span. The facility was an important setting for the band's transition toward a more controlled and spacious production style.

The album credits also list Little Mountain Sound in Vancouver and A&M in Los Angeles. Those additional locations can cause confusion, but One on One is the studio most directly associated with the principal recording sessions. The question therefore refers to the main Los Angeles recording base, not every location appearing in the credits.

Metallica's work there was shaped by producer Bob Rock, whose methods often challenged the band. The finished record's heavy guitar tone, clearer bass presence, and more concise arrangements helped distinguish it from the group's earlier albums.