At which Los Angeles studio did Metallica record most of The Black Album?

Metallica recorded most of The Black Album at One on One Recording Studios in Los Angeles.

The main recording period ran from October 1990 to June 1991. The studio, also identified as One on One in album credits, provided the setting for the band’s first major collaboration with producer Bob Rock. Additional work took place at Little Mountain Sound Studios in Vancouver and A&M Studios in Hollywood.

The sessions were unusually demanding for Metallica. Rock asked James Hetfield, Lars Ulrich, Kirk Hammett, and Jason Newsted to perform more collaboratively, rather than simply recording isolated parts and combining them later. The band also recorded numerous takes before selecting and editing performances.

One on One is sometimes confused with A&M Studios because mixing and additional overdubs occurred at A&M near the end of production. However, the album’s principal studio credit is One on One Recording Studios in Los Angeles.