Andy Johns engineered Led Zeppelin IV. He was also a little bit of a madman.

Yes, Andy Johns was the engineer (with Jimmy Page producing). He used a bunch of unconventional techniques that are half the reason that album sounds like a bomb going off in a cathedral.

Most famously, they recorded at Headley Grange, a damp old house with terrible acoustics. Instead of fighting it, Johns and Page leaned in. They set up Bonham’s drums in the main hallway with its stone floors and high ceilings – no baffles, no isolation. The natural reverb is all over “When the Levee Breaks.” They also used a Binson Echorec for tape delay on vocals and guitars, and Johns ran the drum tracks through a one-of-a-kind tube compressor (an Altec 436C) that was already dying, which gave them that giant, smashed sound. Mic placement was weird too: he often placed a single ribbon mic far down the hallway for room sound, none of this close-mic-only stuff.

None of it was by the book. It was all about capturing the energy of the room and the band, not removing it. You can’t fake that with plugins.