seventh chords with minor scales?

[Bob]

For minor scales....

The first five notes are stable.  That's no problem with the scale, traids built on those steps, or sevenths built on those steps.

If you're going up, a raised 6th and raised 7th step sound good for the scale.  Melodic minor.  Lowered 7th and lowered 6th on the way down the scale.

I think it sounds good to keep that when playing triads over the scale, to some extent. 
V bVI viio i  on the way up.
i bVII bVI V on the way down.
That sounds ok to my ear. 


I'm kind of confused when I take that to seventh chords though for minor.

The first five steps seem fine.


iM7 iimhalfo7 IIIM7 ivm7 V7


After that I'm still thinking.
Although this sounds ok... Maybe...
V7 bVIM7 viidimo7 im7 on the way up.


On the way down I'm less sure...
im7 bVII7? bVIM7 V7
? I'm wondering if a dominant seventh on the lowered seventh step is ok.  I suppose it's just a passing dominant seventh though.  bVIIM7 doesn't sound right. 

Any thoughts?

[jlh]

I think bVII7 is the only thing it could be.  Descending melodic minor is also natural minor or aeolian mode, so I think you would have to remain diatonic to the new scale played on the way down wouldn't you?

[Bob]

I think I found what I was looking for. 

V7 bVIM7 viio7 im7 on the way up and down sound ok.  That's building it off the harmonic minor.

Off the melodic minor, I found in a book by Valerio...
V7 vio7 viio7 im7, ascending
im7, bVII7, bVIM7, V7 descending

It depends what you want.  That should work for what I was thinking of though, packages it up nicely.  Easy learning.

[ted]

Could someone explain to me why it is necessary to play any particular formation with any other. Discussions like this leave me utterly perplexed. Endless heated diatribes I wouldn't dare enter sometimes take place on Pianoworld about which chords are right and which wrong, funnily enough, more especially when jazz is involved rather than classical.

Is this sort of thing only relevant for old-fashioned music, or if we are trying to scrupulously imitate a particular idiom of the past ?  Am I some sort of aural fruit-cake in simply treating harmony as a more or less arbitrary surface phenomenon ? How can "right" or "wrong" chords possibly exist in any universal sense ? 

[Bob]

It helps me to see them in context.  And I've got some exercises I made up based on scales.  It seems to make a difference to my brain if it's just a plain C Major (which I think I start seeing as a tonic) versus C Major as a IV or V.