Rudy Van Gelder, Audio Engineer Who Helped Define Sound of Jazz, Has Died

Producers typically focus not on the mechanics and apparatus of the recording process/audio fidelity (that's what the engineer does) but rather are involved in selecting the musicians who play together, what songs they record, how they're arranged, mixed, sometimes even contributing to the writing, etc.

Given that most of those responsibilities don't apply in traditional jazz - Coltrane is going to play with whoever Coltrane wants to play with - and the "mix" is intended to match as closely as possible how it sounds in a real life setting, the role of "producer" (outside of the artist themselves) in most traditional jazz was never really a thing.

But, a major motivation to remaster old records is due to copyright expiring on the old recordings, particularly in Europe. A remastered release is considered a new release in terms of copyright, which can therefore be protected, I believe.

The depressing mountain of very cheap public domain John Coltrane (for just one example) "reissues" by every man and his dog was foreseen by the record companies.

And, while I'm here, these cheap reissues of expired copyright recordings often say they are "remastered" when all they've done is tweak the equaliser and added some phasing. For no other reason, these RVG remasters are great in order to identify the reference recording amongst the deluge of bedroom re-hashes.

(And, RIP Bobby Hutcherson. RVG's remasters of his recordings sparkle).