Why Are There 3 Minor Scales?

Natural minor, harmonic minor, melodic minor….There is only ONE major scale, so why 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.

There are 3 minor scales, or more precisely, 3 variants of the minor scale because of how harmony and melody interact in tonal music. So what is tonality in music? Tonality (also known as ‘tonal music’) is music that has a tonic (T or “I”) – that specific note on which music is the most stable and at rest.

In general, tonal music works by establishing a tonic, moving away from it and then returning to it. Composers change some notes of the minor scale to achieve a specific sound for a particular style.    

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.

It is importatnt to mention that the harmonic minor scale was derived by the need for a Dominant chord on the 5th degree (V) of the minor scale - enabling a Perfect Cadence (a Dominant 7th V chord resolving to a I minor chord).

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: