Melodic minor

It is derived from the Natural Minor Scale with a raised 6th and 7th degree but can also be thought of as a Major scale with a flattened 3rd.
In Classical music theory the melodic minor and natural minor are combined into one scale. The melodic minor is used when ascending the scale, the natural minor is used when descending the scale. This idea is not used in a jazz environment and in modern music is somewhat redundant, except in high school classical music study.

Scale Formula

The scale forumula for the major scale must be memorised, as you will use it often to work out chord tones. The formula describes the interval distances between each note of the scale.

T ^ S ^ T ^ T ^ T ^ T ^ S
(T=Tone, S= Semitone)

Comparison With Major Scale

C Major = C D E F G A B C (1 2 3 4 5 6 7 1)
C Melodic Minor = C D Eb F G A B C (1 2 b3 4 5 6 7 1)

And here’s a pattern for D melodic minor. Why D melodic minor? Hang tight: play first and we’ll answer questions in a bit.

|------------------|--------------------|
|--------------2-3-|-3-2----------------|
|----------2-4-----|-----4-2------------|
|----2-3-5---------|---------5-3-2------|
|--5---------------|---------------5----|
|------------------|--------------------|

Get acquainted with this pattern and play it over the G7 chord. If you already know a few major scales, this pattern is real close to one you know: the D major scale. As just mentioned, there’s just one note difference between the major and melodic minor scales.
What did you think of the sound? That gets us into answering the question: why are we using a scale whose root is D to solo over a G7 chord? Is it magic, or are we just playing scales at random?
No, we’re not just choosing any scale. Let’s look at the notes in G7 and those in the D melodic minor scale:
G7: G B D F
D melodic minor (starting with G): G A B C# D E F G.
You see that the D melodic minor scale contains the G7 chord with no conflicts. That is, every note in G7 is found in D melodic minor.
But notice something else: The D melodic minor scale has just one accidental: C#. The whole scale is extremely close to the C major scale — just one note different. This means that if you’re playing a tune that uses the C major scale and come across a G7 chord, you can play the D melodic minor scale instead of the C major scale; you will sound interestingly different, but not so different to where you would consider the sound wrong or ugly.
Next time: another way of using the melodic minor scale to play over a Dom 7 chord.

5 positions of melodic minor
E

D

C

A

G