Keith Harwood and the 24-track revolution at Musicland Studios for It's Only Rock 'n Roll

The Rolling Stones made a sharp left turn in late 1973 when they decamped to Munich’s Musicland Studios to record It’s Only Rock ’n Roll. The move was partly tax exile pragmatism, but the studio itself was a draw—one of the few in Europe equipped with a 24-track Ampex MM-1100 tape machine, which the Stones had never used before. Up to that point they had been working with 16- or even 8-track setups, so the extra tracks gave them room to layer vocals, percussion, and guitar overdubs with a density they hadn’t attempted before. Keith Harwood, a young English engineer who had cut his teeth on Led Zeppelin’s Houses of the Holy, was brought in to run the sessions. He ended up becoming a crucial part of the album’s sound.

Harwood’s approach was hands-on and slightly chaotic, which suited the Stones’ mood in Munich.