“I know Pagey made me mix the outro section half a dozen times: ‘Not enough of me, dear boy! Not enough of me, make me louder!’” – Andy Johns on the challenges of engineering Led Zeppelin's Rock And Roll
In 2011 the acclaimed engineer revealed some of the realities behind making Led Zeppelin IV: 'John’s got his hi-hat nearly all the way open and that was bleeding all over the place'
https://www.musicradar.com/news/led-zeppelin-rock-and-roll-jimmy-page-andy-johns-interview