Bombay:
I may have given you the incorrect impression about the SACD versions of the "Louis Plays" recordings. If you own/have listened to the redbook versions of these recordings, in a few places, the recording of the brass is so harsh as to be painful. My guess is that this was a fault of how the performance was captured on tape, as opposed to the musician's playing technique. Armstrong's bands were known for little turnover among band members and for being well rehearsed with little deviation from their play book.
Live brass has more than just bite to its sound ... it has incredible volume to its sound and the recording equipment probably maxed out in this case. The SACD version softens this maxing out a touch. To my ears, reducing the harshness made sense, as the recording is more listenable, while retaining its original character. You may want to seek out these recordings and judge for yourself ... I would be curious as to your comments.
Regards, Rich