Talk:Jazz scale

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My recent edit merely corrected what was an oversight, I'm sure. Modes can be presented in relative (same pitch classes) or in parallel terms (same letter-name scale degrees). Both are handy didactic terms and it's easy to confuse them, which is what happened here on the 2nd and 7th degrees: it is the parallel Phrygian #6 and Super Locrian of C melodic minor that take a C7 sus b9 and a C7 #9 b13, respectively, but the rest of the presentation is relative to C melodic minor.

I wonder if it isn't worth pointing out why the ascending melodic minor scale is such a powerful tool: We divide 12 chromatic tones into 7 "letter-name" steps. Assuming no interval greater than the enharmonic equivalent of a major second, that necessarily produces 5 whole steps and 2 half steps (5 x 2) + 2 = 12. There are only three ways to do this:

1. separate the 1/2 steps as much as possible, i.e. by 2 & 3 whole steps (W W H W W W H). This yields the traditional diatonic modes.
2. group the 1/2 steps together (W W W W W H H). This is the enharmonic equivalent of a whole tone scale with one of the half-steps filled in, and yields a set of modes where "minor" sounds and "major" sounds are both present in extremes. (Think of a major scale with b2 and b3, or a Lydian scale with a b6 and b7.)
3. The middle ground: separate the 1/2 steps by 1 & 4 whole steps (W H W W W W H).

The ascending melodic minor scale is how this last option has traditionally been used. In a minor context, a composer wanted a melody to "rise" to the tonic, via step-wise approach to the leading tone. I don't think it is an accident that this formulation began as a melodic convention and was only much later (and unwittingly) incorporated into a harmonic scheme. We tend to forget that, historically speaking, harmony is a (contrapuntal) emergent property. Sinnis 14:43, 6 February 2007 (UTC)