Diatonic Modes

Interested in learning more about diatonic scales?

Diatonic scales are an important part of music theory and can be used in various ways to create interesting-sounding melodies and chord progressions. In this guide, you will learn about the seven diatonic modes and how to use them in your own music.

Once you have learned about the different diatonic scales, you can start using them to create your own music.

Read the complete article to know all diatonic modes completely!

What is a Mode?

Before we dive into our main topic, let us begin by creating our concepts about what a mode is. Consider “A” minor pentatonic scale, which you all know is a collection of five notes with a particular set of intervals between its notes, and A, its tonic note.

The scale formula for the minor pentatonic scale is {TS T T TS T}, where TS is an interval of three semitones, T, two semitones, and S – one semitone.

Based on the above scale formula, the intervals between all the notes of the scale and the tonic note are R, m3, P4, P5, and m7. As you know, from the music theory, the intervals (m3, P4, etc.) define the notes’ relative positions in the scale. The notes of the A minor pentatonic scale are [A, C, D, E, G].

If we reorient the above five notes by taking any other note from the collection and considering it a tonic note without disturbing the sequence, we will obtain a mode of the original scale.

The original scale [A, C, D, E, G] is considered the first mode of itself. As it is a pentatonic scale, it will have five modes. The other modes are:

The Second Mode – [C, D, E, G, A],

The Third Mode – [D, E, G, A, C],

The Fourth Mode – [E, G, A, C, D], and

The Fifth Mode – [G, A, C, D, E].

As you can see, it is the same collection of five notes. We have only changed the tonic and kept the notes in the same sequence as the original, which means G is always preceded by E and succeeded by A unless it is the first or the last note in the mode.

It is important to observe that while the sequence is maintained, the intervals between the notes differ in different modes. Let us consider the second mode [C, D, E, G, A] to understand this. In this mode,

• C is the tonic note,
• D is two semitones away and is at the major 2nd interval from the tonic,
• E is at the major 3rd interval (4 semitones).
• G is at the Perfect 5th interval (7 semitones).
• A is at the major 6th interval (9 semitones).

So, the intervals for the second mode are R, M2, M3, P5, P6, and the mode or scale formula is {T T TS T TS}. We know this is a C major pentatonic scale, a very common scale in blues, rock, country, and pop music. All the other three modes have a different set of intervals also and are completely different scales.

You can use the terms “modes” and “scales” interchangeably,

What is a diatonic Mode or scale?

We call a scale “diatonic” if it is a mode of the major scale. The Greek meaning of the word diatonic is “across the octave.” This implies that the notes of diatonic scales (also known as the heptatonic scales) are evenly distributed across the octave.

This can be easily observed as you will never find a TS interval (3 semitones) between two notes in any diatonic scale. All the half-step intervals are separated by at least two full steps. There are always five full steps and two half steps in any diatonic scale.

There are seven diatonic scales, also called diatonic modes, in one diatonic structure. So you can call the most basic seven-note scale the diatonic scale. Major scale and natural minor scale are part of this arrangement.

Chords originating from the major scales are called diatonic chords. Each of the possible major scale keys (Twelve) will have its own set of seven chords from the seven notes in each key.

The diatonic modes are also referred to in various texts as the church modes, established for religious music in the medieval era.

7 Note Diatonic Natural Major Scale

As highlighted above, the structure of the seven-note major scale is relatively even, as shown below. Note that all the intervals mentioned below are from the tonic note of the scale.

1. Tonic Note – R,
2. Major 2nd – M2,
3. Major 3rd – M3,
4. Perfect 4th – P4,
5. Perfect 5th – P5
6. Major 6th – M6
7. major 7th – M7

The scale formula is {T T S T T T S}. This scale has no TS interval, and all S are separated by at least two T’s. The seventh note is just a half step away from the octave and known as the leading tone. We can represent the scale as

R – T – M2 – T – M3 – S – P4 – T – P5 – T – M6 – T – M7 – S – R (Octave)

The root note can be any of the 12 notes used in the chromatic scale of Western music. This structure represents the form of all the diatonic scales, as they are just modes of each other and will only start at a different point in this structure. Considering the key of C,

C – T – D – T – E – S – F – T – G – T – A – T – B – S – C.

This is the C major scale, considered special as it contains only the natural notes without any sharps and flats.

What is a Scale Degree?

Assigning Scale degrees is the numerical method of describing the scales.

If you arrange the eight notes of any scale (seven notes and the octave note) in ascending order of pitches, each note in any scale is assigned a number in ascending order starting from 1, known as its scale degree. Each note is also given a special name to describe its function and of the chord built on it as the root. The names of the scale degrees are

• First Note and Last Note or First Scale Degree – Tonic center or the natural resolution point for all the notes in the scale.
• Second Note or Second Scale Degree – Supertonic or “above the tonic.”
• Third Note or Third Scale Degree – Mediant, since it is between tonic and dominant scale degrees. It is also the median or middle of any minor or major triad built with the first-degree note.
• Fourth Note or Fourth Scale Degree – Subdominant, one note below the dominant.
• Fifth Note or Fifth Scale Degree – Dominant. This is the second most important scale degree. Most pop, classical and contemporary music depends on the resolution of the dominant to the tonic center for cadence.
• Sixth Note or Sixth Scale Degree – Submediant lies between the tonic (octave) and subdominant.
• Seventh Note or Seventh Scale Degree – Leading Tone. Scales with the seventh note one semitone away from the octave tonic are known as leading tone scales. So they have a natural tendency to resolve to the tonic. Example – The major scale.
• Eighth Note – Tonic in a higher octave.

What are the 7 modes?

To recap, a mode is just a reorientation of any scale by changing the tonic but keeping the notes the same as in the original scale. The harmonic center changes as the tonic changes, even if the notes are the same, due to the change in the set of intervals.

With this background, let us start spelling out the diatonic modes with a major scale as the primary mode. Any diatonic scale has seven notes, resulting in seven modes, each having a unique name assigned in ancient Greece time. We will use the C major scale to define the following modes.

Ionian Mode (First Mode)

The first mode, known as the Ionian mode, is the normal, natural major scale. In the key of C, the notes are [C, D, E, F, G, A, B], and the intervals are R, M2, M3, P4, P5, M6, M7.

This mode provides a happy, melodic, and consonant sound, being a major mode.

Dorian Mode (Second Mode)

The notes of the 2nd mode, known as the Dorian mode, are [D, E, F, G, A, B, C]. D Dorian has all the notes as C Ionian but has a different tonal center.

To arrive at the Dorian mode, we have used the same notes, starting at the second note and using the same sequence of the notes as in the major scale. We can do the same for the scale formula to obtain it without going through the intervals – {T S T T T S T}.

From the scale formula, the intervals are R, M2, m3, P4, P5, M6, and m7. In expanded form

R – T – M2 – S – m3 – T – P4 – T – P5 – T – M6 – S – m7 – T – R

This is considered a minor mode, as it has a minor third. Because of this, it is darker sounding than the Ionian mode, but the major sixth makes it brighter than a natural minor scale. It is used in blues and jazz.

Phrygian Mode (Third Mode)

The Phrygian mode starts on the third note, E of the C major scale, and contains the notes [E, F, G, A, B, C, D]. The scale formula for the E Phrygian mode is {S T T T S T T}, and the intervals are R, m2, m3, P4, P5, m6, m7. The expanded form is

R – S – m2 – T – m3 – T – P4 – T – P5 – S – m6 – T – m7 – T – R

Being a minor mode, it is dark sounding, but a minor 2nd makes it exotic. A minor second is a dissonant interval, only a half step away from the root, and tries to resolve to the root. It finds use in some metal, jazz, Flamenco, Latin and Indian music.

It is quite similar to the 6th mode, with the only difference being a lowered scale degree of 2 – m2 instead of M2 in the 6th mode.

Lydian Mode (Fourth Mode)

The Lydian mode starts on the fourth note, F, of the major scale. Its notes are [F, G, A, B, C, D, E] governed by the scale formula { T T T S T T S}. The intervals for the Lydian mode are R, M2, M3, A4, P5, M6, M7, with the expanded form,

R – T – M2 – T – M3 – T – A4 – S – P5 – T – M6 – T – M7 – S – R

The only difference between this and the first mode is the A4 instead of the P4 interval, i.e., mode one has a raised scale degree 4. This makes it a pleasant-sounding and exotic major mode. The subtle dissonance makes it a bit complex. It finds use in jazz in place of the major scale.

Mixolydian Mode (Fifth Mode)

The Mixolydian mode (or the 5th mode of the major musical scale) starts with the fifth note as the root and carries [G, A, B, C, D, E, F] as the other notes.

The scale formula for the 5th mode is {T T S T T S T}, which results in R, M2, M3, P4, P5, M6, and m7 intervals between the notes. Its expanded form is

R – T – M2 – T – M3 – S – P4 – T – P5 – T – M6 – S – m7 – T – R

Like, the Lydian, this mode also differs in only one interval from the major scale pattern, having a minor 7th instead of a major 7th. It is a great blue scale with a major mode providing a round and stable sound.

Aeolian Mode (Sixth Mode}

The sixth mode of the major scale is also known as the Aeolian mode. Our exercise for the 6th mode starts with A as the starting note and has [A, B, C, D, E, F, G] as the complete set of notes.

The scale formula becomes {T S T T S T T} with R, M2, m3, P4, P5, m6, m7 as its intervals, giving its expanded form as

R – T – M2 – S – m3 – T – P4 – T – P5 – S – m6 – T – m7 – T – R

You can instantly recognize this as the natural minor mode used in all types of music; it sounds dark and sad. It is also known as the minor scale. It is characterized by a pronounced tension resulting in musical friction.

As we have seen, it is the sixth mode of the major scale. We can find out the relative minor of any major scale by starting at the sixth note of the major scale and following the note structure.

Locrian Mode (Seventh Mode)

Last is the Locrian mode, which starts on the seventh note of the selected major scale, the B note, in our case. The notes are [B, C, D, E, F, G, A] with the scale formula {S T T S T T T} and the intervals R, m2, m3, P4, D5, m6, m7. The expanded form becomes

R – S – m2 – T – m3 – T – P4 – S – D5 – T – m6 – T – m7 – T – R

As seen from the minor third, it is a minor scale that is a bit strange and rarely used. It is the only mode with a diminished fifth interval instead of a perfect fifth in every other mode. Also, the Locrian mode has dissonant intervals as both the 2nd and 5th notes are flat. This mode is heavy, unstable, dissonant, and historically avoided.

Some Observations at a Glance

Let us present the modes, intervals, and notes in a tabular format, giving us valuable insight into the modes.

1. Mode 4 is the only mode with a sharp.
2. Mode 5 has only one flat note.
3. Mode 7 has the maximum number of flat notes, 5.
4. Mode 7 has a diminished note at scale degree 5 because scale degree 4 already has a P4. We cannot have two notes with the same scale degree in any mode.
5. The only difference between mode 3 and mode 6 is at scale degree 2.

Conclusion

That’s all for this lesson on diatonic scales. In the comments section, I would love to hear about your experiences with learning and using diatonic scales in your music. Also, if you have any questions that weren’t answered here, please ask – I will do my best to answer them. Thanks for reading!