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What is a diatonic scale in music? different Types and non diatonic scales

The diatonic scale is that concept that we have heard countless times when learning to play guitar or piano from scratch, and from which we cannot escape because of the importance it has. In fact, if I said that the major scale was the mother of scales, the diatonic scale is the grandmother because it’s one step above.

Therefore, in this post we will learn everything about this music scale, paying special attention to the diatonic scale meaning, the different types and the non-diatonic ones.

What is the diatonic scale?

First of all, I’d like to state that the question “What is the diatonic scale?”is not accurate since it should really be “What is a diatonic scale?”

Because the musical diatonic scale is a type of scale that meets 3 requirements:

  • It has 7 notes per octave.
  • It has 2 semitone intervals and 5 tone intervals within one octave.
  • Its 2 semitone intervals are separated by 2 or 3 tones.

Note: Remember that a semitone is a half step and a tone is a whole step.

So, the first requirement is easy to understand, the second one too, but what about the third requirement? what is this tongue twister I just told you?, let’s see it.

The first thing is to say that based on the first two points we could affirm that the major scale is diatonic. Correct, and to be more precise we could call it diatonic major scale.

So, let’s remember, for eintance, the C major scale, or C diatonic scale:

c major scale formule

And now let’s analyze point 3.

This requirement specifies that the 2 semitone intervals must be separated by 2 or 3 tones.

Well, the first semitone interval (between E and F) is at a distance of 3 tones with respect to the second semitone interval (between B and C). And in turn, the semitone interval between B and C is at a distance of 2 tones from the semitone interval between E and F.

Therefore, the 2 semitone intervals are separated by 2 or 3 tones and we can call it C major diatonic scale.

c major pentatonic scale
Diatonic Scale Guitar

Why is it called Diatonic Scale?

To understand why this music scale is called diatonic we have to jump back in time to the ancient Greece.

The term diatonic, comes from diatonikós, referred to a type of tuning that could be made to the lyre (which were diatonic, chromatic or enharmonic).

Therefore, and to the surprise of many, it has no relation to the tones and semitones of a scale.

How is the Diatonic Scale built?

A very easy and simple way to obtain the diatonic degrees that compose the diatonic scale in any key is by drawing a chain of perfect fifths (in other words, intervals of 7 semitones).

To better understand this concept we are going to take a totally random example: the F note.

Let’s start from F chain perfect fifths and see what happens:

diatonic major and minor scales

As a result, we obtain the following notes:

F C G D A E B

Wait a minute… these notes arranged in an alphabetical order composed the C major diatonic scale:

C D E F G A B

Okay, I will admit that choosing the F note may not have been a completely random example…

But this succession from F is very important. So much so that it’s the structure on which my beloved circle of fifths and fourths is based, and which I use so much to obtain major and minor scales and chords.

circle of fifths chart
circle of fifths chart

In fact, if we put the electric guitar aside for a moment and switch instruments to look at the keys of a piano, we’ll see that all the white keys form the C major diatonic scale.

diatonic scale piano

Types of Diatonic Scales

Now that we have understood how the diatonics scales are constructed you will understand that there are different types of diatonic scales.

For example, if we start from the major scale, which has the following interval distribution:

W W H W W W S

As we move through its different musical modes (Dorian, Ionian, Phrygian…) we’ll see that we’ll always be in a type of diatonic scale.

Why? Because the interval distribution is always the same and the semitones are always separated by a distance of 2 or 3 tones:

  • Ionian: W – W – H – W – W – W – H
  • Dorian: W – H – W – W – W – H – W
  • Phrygian: H – W – W – W – H – W – W
  • Lydian: W – W – W – H – W – W – H
  • Mixolydian: W – W – H – W – W – H – W
  • Aeolian: W – H – W – W – H – W – W
  • Locrian: H – W – W – H – W – W – W

This is why, they are called “The 7 diatonic modes” or “The 7 Modes of the Diatonic Scale”.

Moreover, if we remember that the natural minor scale is the Aeolian mode of the major scale, we can affirm that the natural minor scale is a diatonic scale as well and we can call it minor diatonic scale:

major and minor scale
🎵 What are diatonic scales?

As a summary, we can say that major scales, modal scales and the natural minor scale are all diatonic scales.

With that being said, there are many scales that are not diatonic.

Which Music Scales are not Diatonic?

Unlike the examples seen in the previous sections, there are other musical scales that are not diatonic.

In order to see which are non diatonic scales we have to remember one last time the diatonic scale definition:

  • It has 7 notes within one octave.
  • It has 2 semitone intervals and 5 tone intervals within one octave.
  • Its 2 semitone intervals are separated by 2 or 3 tones.

Great, so reading the first line I can see that the pentatonic scale is not diatonic. Why? Well, first of all because it doesn’t have 7 notes:

a minor pentatonic scale degrees
C Minor Pentatonic Scale
major pentatonic scale degrees
C Major Pentatonc Scale

Likewise, the blues scale is not diatonic either. It’s true that now we have notes separated by semitone intervalss, but not at the required distance, and we still don’t have 7 notes.

g minor blues scale

What about the musical chromatic scale? It’s not diatonic either.

c chromatic scale

The reason is that this musical scale is composed of too many pitches. As a result, there is no diatonic chromatic scale in music.

🎵 Diatonic Scale vs Chromatic

The main difference between the diatonic and chromatic scales is that the first one uses seven notes and the second one uses all 12 pitches within one octave.

If we move on to other minor scales, we can say that the harmonic minor scale is not diatonic either since, although it is a heptatonic scale, it has neither 2 semitone intervals nor 5 tone intervals, as we see below:

a harmonic minor scale

Finally, the melodic minor scale, with its 4-tone distance between its semitones is not diatonic either:

Diatonic Chords

Closely related to the concept of the diatonic scale is the subject of diatonic chords.

As we saw in the major scale harmonization article, we can create chords by taking third intervals.

Therefore, if we build chords based on a diatonic scale we will used the diatonic notes and, as a result, construct the so-called diatonic chords. In other words, if we take the diatonic major scale and harmonize it, we obtain the diatonic chords of that scale.

Well, Well, that’s all for now, the study of the diatonic scale ends here. I hope you have learned a lot about the subject.

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