DH says of the Salonen M9th,
"For some reason Salonen plays the tam-tam crash at the movement's climax as a tremolo, an odd decision, but at least it's audible. "
But I am not sure if he realizes that all of Philharmonia Orch. recordings of M9th have the same treatment of tam tam. For this reason, it must have been the percussionist's decision, not the conductors'.
John,