The difference I'm referring to is in
why the track was created. Not in how you or I might use it.
A group goes into a recording studio to record a song.
In the old days, they would have recorded it "live" with everybody doing their thing all at once. (Usually resulting in a lot of takes.)
With the advent of multi-tracking, they can now lay down a rhythm track (
backing track), usually with drums, bass and maybe some guitar.
Then they can come back later, either together or separately, and
overdub vocals, solos and whatever.
Now-a-days they can even record each individual thing on a separate track.
And even email the backing track to other artists anywhere in the world for their input.
The link provided in the OP is selling (Legally??)
actual backing tracks to
actual songs that were actually recorded by actual "well known" groups.
Some groups record backing tracks to use during a performance. This way they can add instruments and parts they wouldn't otherwise be able to play live. Some might even record the main vocal and just sing along (or pretend to sing......Ashlee Simpson on SNL??
).
(Think of seeing a computer on stage and hearing backup singers that you can't seem to find onstage anywhere.)
I first saw this sort of thing in college when Josh White Jr gave a "solo" concert backed up by a big ol' reel to reel tape player.
A jam track is usually a "generic" example of some kind of specific type of progression, usually done by some commercial outfit that records tracks for practicing and working on improvising. They may be in the "style" of some well known song, but they are not the actual backing track used by the original artist.
Last April we had a challenge learning Griff's song "Someone" from his new CD.
He provided his actual
backing track and our job was to overdub chords, the solos and even vocals, if we wanted to.
This was not a jam track for improvising our own solo. It was to try to re-create Griff's song, note for note.
He also has several collections of jam tracks, covering a variety of styles and feels in a variety of keys. These are for improvising.
Sure you can jam over a backing track and you can overdub parts to a jam track.
But those weren't the intended purposes they were originally recorded for.
**A backing track is created for backing and a jam track is created for jamming.**
Seems too simple.
Disclaimer: These are not "official" definitions. And I did say there's a difference for anyone who feels "nitpicky".
I love the disclaimer; I do it too.
Good explanation, never really gave it a thought ... and was incorrect all these years.
BTW, IMHO, I don't much like how much post processing goes into music. Music for me is all at once.