Natural minor, harmonic minor, melodic minor, WHAT?!
There is only ONE major scale, so why the heck are there 3 minor scales? And what’s the difference between them?
The big difference comes down to the role or function of the notes.
What do I mean? Let me explain.
The Natural Minor
This is the minor scale in its most basic form. Every major scale has a ‘relative’ minor. G major has one sharp (F#). Its relative minor is Em, which also has one sharp (F#).
The notes of Em are exactly the same as G major, just starting on E. This is the ‘natural’ minor. The scale is played according to its key signature, and looks like this:
This is probably the most commonly used minor scale, especially in popular music.
It sounds fine -- but there’s not real ‘pull’ to the final note. It sounds a little bland. Music is all about 'tension' and 'resolution', and we don't find too much of that here.
The Harmonic Minor
In music, the 7th note is called the ‘leading note’. It ‘leads’ the ear towards the next note, which is often the tonic (root or 8th note). Its role is to create that tension and make us want to hear a resolution. In the natural minor, there is no strong leading note function.
That’s where the harmonic minor comes in. This scale raises the 7th note by a half-step, so D now becomes D#. This creates a lot of tension, that wants to resolve as we reach the E.
Here's the scale in the treble, with the natural scale in the bass for comparison:
That D# creates a lot of tension now, and our ears really want a resolution.
As the name implies, the harmonic minor scale is used a lot in harmony and chord formation.
But there's still a problem, so we need ...
The Melodic Minor
So now we have a raised 7th that creates some nice tension -- but it also creates a big gap between the 6th and 7th note. It’s 3 half-steps. That gap is quite ‘crunchy’ to the ear and a little harsh.
In order to make that sound less harsh, and create more opportunities for melodies, we need to close that gap.
The melodic minor scale does this by raising the 6th note as well as the 7th. In Em that’s the C#. It gives us a much nicer approach to the tonic (the E) while still wanting to resolve. Here's how it looks, with the natural minor in the bass for comparison:
Now the biggest and weirdest thing you may notice is how the melodic minor scale is DIFFERENT going up than it is going down. What happened to all those sharps?
When we go back down - the 7th and 6th notes are returned to the natural scale. So the D# is just a D, and the C# is just a C.
Why? Why on earth would they make things this complicated??!!!
It all has to do with direction. Remember when we are playing UP the scale the 7th is the 'leading note'. It's leading us to the tonic. When we play DOWN the scale we are moving AWAY from the tonic, so we don’t need those raised notes to ‘pull’ us towards the E.
This is the least used of the minor scales, so if it’s a little confusing, don’t worry too much! It's mostly used in classical music.
The One Takeaway
Minor scales are super fun to learn and play. Start with the natural minor, because it is the easiest to learn and remember, and it's also the most common minor scale used in popular music.
Learning the natural minor scale first will give you lots of ways to practice, and once you feel comfrortable you can start playing around with the other scales to create some very cool sounds.