NOTATION 33 (& THEORY): Melodic Minor
For those of you planning to take a theory grade, one of the perennial questions is to identify the Melodic Minor in action.
Here is a classic example:
The key is Dm = D E F G A Bb C but notice the two accidentals B natural and C sharp used for the ascending phrase.
The Melodic Minor version of Dm is : D E F G A B C#, so it confirms your suspicion and you get a few marks. See NOTATION 25 for related.
Bach chose to use those notes there because they suited his composition. There is a pleasant sound to the new notes when used like this - since the scale is taught in the classical world as played ascending with the major 6th and 7th, but descending as was in the natural minor.
This encourages orthodox composers to follow suit and when used like this are also considered Diatonic (from the key), but the implication in the way the scale is taught is that they are nevertheless notes for special occasions.
In Jazz and Progressive spheres those notes are fair game in any direction and also permeate the chordal landscape in profound ways (I have found the scale in modern books called the Jazz Minor). Take a look at what happens to the regular key,s worth of chords when you tamper with the original notes in THEORY 2.
A simpler way to view this is that if you start with a simple predictable sounding seven note key like Dm, then regardless of the jargon, that leaves only five notes for spicing up your ideas with colourful notes: b2 = Eb, 3 = Gb, b5 = Ab, 6 = B, 7 = C#.
The 6 and 7 are by virtue of the Melodic Minor and sound familiar if used like Bach, but in other contexts can sound ‘outside’ if not used with care.
The b5 sounds familiar in a Blues soloing context, but like the 6 & 7 can be a really challenging note to make work in other contexts, and especially as part of regular chords generated by the simple original key you chose.
b2 and 3 are rank outsiders, but like the others, they just need careful consideration, deft technique and crafty phrasing to bring them into the fold when required.
The concept of what is outside is purely subjective. If you listen to a tune by Hank Marvin and then one by Robert Fripp, you can hear how varied people’s taste is. If Hank sounds familiar then Robert will sound outside, and visa versa.
95% of historically published and recorded music is based around the simple seven note keys, and a large portion of that really only uses five (based on the Pentatonic scales). It took pioneers like Debussy, Stravinsky, Davis and Zappa and King Crimson to delight the imagination and inspire people looking for something different.