Intrada Soundtrack Forum

I just discovered this new wing of the forum today; thank you for offering us this service, Doctor! My particular question comes from the low-information portion of this demographic, so you might possibly settle it with a very short answer.

During the past few years, I've read in liner notes and quite a few forum discussions many references to "music stems" being used as sources for CD releases when the original master recordings of a score were not available (or incomplete). Since I come from the era of analog film elements, so far I've just made assumptions about this -- but are music stems what used to be the mono mixdown of music laid to 35mm film, after volume adjustments were made to accommodate dialogue/sound effects, but before that fluctuating-volume mix became a source for the music-and-effects track? Or are they something else entirely?

In case I'm displaying a void of ignorance that requires more than a short confirmation to fill, I apologize for your time but would also appreciate the effort behind a detailed explanation. Thank you so much for the gift of knowledge, Doc!

Thanks, Doctor, I'm satisfied. Tell you what -- I'll follow your orders to keep on rocking those soundtracks!

Thanks for that info. Does the element (eg 35mm) contain all three channels of the mix (Dialogue, music and effects)? If so, how might "bleed" occur if each is originally relegated to its own channel?

Thank you Doc.