From memory, 40 years ago: Nelson Barden interviewed Julius Chaloff who
had been an Ampico editor, and Chaloff related a story about Schmitz.
They made a test recording [for an Ampico roll] and found it so loud
"it would drive you out of the room."  They checked and rechecked the
dynamic levels, and that was exactly how Schmitz had played.

They finally concluded that the force of his personality allowed him
to play that way, but when he was no longer on the bench, they had to
reduce the dynamics on the roll to make it saleable.

Alan Douglas