[throwaway1004]

The engineers invovled would certainly be responsible for this, Rubin himself has little-to-no technical ability or involvement with the actual process of creating music, instead he provides commentary, veto, and direction towards a high-level objective for the product being produced. But, he almost-certainly was the guy who told Slayer "yeah... that... playing really fast and loud, all the time... keep doing that..." and we all owe him for that!