Dominant subs: V7 by IIm6

Pedro Batista ( PBATISTA@colep.mailpac.pt )
26 May 97 14:45 GMT


Forgive me to go into the chord sub subject again, but I need an expert
opinion!
I've frequently seen dominant chords of the type V7(9) substituted by a m6
chord a perfect 4th below, for ex: G7(9)/D == Dm6(11)
As I understand it, this approach is taken from ascending melodic scale,
where the 4th grade (lidian b7= IV7(9,#11,13)) has the same function of the
1st grade (melodic minor = Im(7M/6,9,11)).
The same sub can be aplied to the subV7 : G7(b9,b13) == Db7(9,#11,13) ==
Abm6
Now, I use this sub a lot, because it sounds nice, and has a misterious sad
ring that provides a interesting variation from the plain V7, but I would
like to know the justification for it.
Is my assumption about the melodic minor scale correct?
Can the same sub be used with other dominant modes, besides lidian dominant?

Shouldnt I be concerned about this (and just use it)?

Thanks,
Pedro