C Jazz Minor over a tonic minor Cmin7 -- why does it sound right?

[christianm77]

Because chord scale theory does not include the structural importance of semitone resolutions in melodic lines.

In other words - leading notes (chromatic lower neighbours) resolving to chord tones ALWAYS sound good.

Also there are a great many jazz lines that include the line cliche 1-7-b7-6 over the minors in a ii-V-I and in their function as a relative minor.

I tend to regard the m7 chord as a suspension of the m6 - m6 and dom9 are intimately related. So it's not so much a ii-V-I as a Vsus-V-I or a ii7-ii6-I. Which basically means V-I of ii6-I. Transcriptions seem to bear out this kind of thinking, which I've heard talked about by Barry Harris among others.

[christianm77]

Or alternatively - who cares? You've noticed that major 7ths sound great on minor chords. That's what all the greats do. Stop worrying about it being 'right' and play some music :-)