The major scale (part 2)

How many major scales are there?

In the last article we learned how to build a major scale from any note. We can conclude that we just need to apply the formula:

WS  WS  HS  WS  WS  WS  HS

WS = whole step
HS = half step

As we saw, all major scales have 7 different sounds but we must begin and end with the same note, so in the end, all major scales will have 8 notes. For example, C major scale: C D E F G A B C (begins and ends with C). F major scale: F G A Bb C D E F (begins and ends with F). We also said that we cannot repeat nor skip note names in the same scale. This is why the F major scale cannot use A#:

F  G  A  A#  C  D  E  F

As we can see, A# is the same note that Bb on the piano (they are enharmonic), but it is technically incorrect to use A# in the F major scale. This is because we would use A twice and skip B. So, the right solution is to use Bb instead. In this way we will have all the note names in our scale:

F  G  A  Bb  C  D  E  F

Double accidentals

Technically speaking, we cannot build major scales from any note. For example, there is not a G# major scale but there is an Ab scale instead. Let's see why this happens:

1. We start on G#
2. Whole step ahead: A#
3. Whole step ahead: B# (we cannot use C because we can't skip the B note name)
4. Half step: C#
5. Whole step: D#
6. Whole step: E# (we cannot use F because we can't skip the E note name)
7. Whole step: ??? G?

As we can see, every note becomes "sharp" and it's harder to understand and visualize that way. Besides of that, we have to use E#. It would be easier to use F instead, but we cannot skip the E note name. Another problem is that one whole step ahead of E# is F double sharp! This situation is called double accidental and we write it Fx. Fx is enharmonic of G and, clearly, double accidentals make everything much more confusing! In a similar way, we could have a double flat, which is written bb (Abb, Cbb, etc.). Anyway, if we build our scale from Ab instead of G#, we won't get any double accidental nor enharmonic craziness:

Ab  Bb  C  D  Eb  F  G  Ab

This way is so much easier to read and understand. In a similar way, we should use Eb instead of D# major scale, and Bb instead of A# major scale.

The 15 major scales

On the other hand, there are also enharmonic "valid" scales. For example, we can use Db or C# major scales. Both are valid as they don't have double accidentals, but in this case, Db is more common as it uses less accidentals:

Db major scale: Db  Eb  F  Gb  Ab  Bb  C  Db

C# major scale: C#  D#  E#  F#  G#  A#  B#  C# (all sharp notes)

Following this, here there are the 15 major scales valid in modern harmony:

C, C#, Db, D, Eb, E, F, F#, Gb, G, Ab, A, Bb, B, Cb.

It's a great exercise is to build and play all of them in different ways. Every professional musician should be able to play well in any of these 15 scales. 

If you want to learn more about harmony and theory, check out my online course: Applied Modern Harmony, part 1!