“In this section the pianist may utter an occasional grunt, puff, or wheeze to give emphasis to a particular note, as classical performers frequently do, apparently without being aware of it.”
-Frederic Rzewski, in the score to “De Profundis“
In case you didn’t know, this performance of the Hammerklavier sonata by Rzewski himself exists, and it’s just as crazy as you might think. Go now and listen. It’s worth the hour.