Basics

The 7 modes of the major scales are typically arranged according to scale degree as such :

Mode Tonic relativeto major scale Interval sequence Example
Ionian I W–W–H–W–W–W–H C–D–E–F–G–A–B–C
Dorian ii W–H–W–W–W–H–W D–E–F–G–A–B–C–D
Phrygian iii H–W–W–W–H–W–W E–F–G–A–B–C–D–E
Lydian IV W–W–W–H–W–W–H F–G–A–B–C–D–E–F
Mixolydian V W–W–H–W–W–H–W G–A–B–C–D–E–F–G
Aeolian vi W–H–W–W–H–W–W A–B–C–D–E–F–G–A
Locrian viiø H–W–W–H–W–W–W B–C–D–E–F–G–A–B

Table 1 : Modes of the C Major scale

This is a great intro to the world of modes and requires minimum pre-requisutes. However, if we look at all the modes with a fixed root, a new pattern starts to emerge.

Taking C as the root, we get :

Mode Notes
Ionian C - D - E - F - G - A - B - C
Dorian C - D - E♭ - F - G - A - B♭ - C
Phrygian C - D♭ - E♭ - F - G - A♭ - B♭ - C
Lydian C - D - E - F# - G - A - B - C
Mixolydian C - D - E - F - G - A - B♭ - C
Aeolian C - D - E♭ - F - G - A♭ - B♭ - C
Locrian C - D♭ - E♭ - F - G♭ - A♭ - B♭ - C

Table 2: Modes with C as root

Mode Notes
Lydian C - D - E - F# - G - A - B - C
Ionian C - D - E - F - G - A - B - C
Mixolydian C - D - E - F - G - A - B♭ - C
Dorian C - D - E♭ - F - G - A - B♭ - C
Aeolian C - D - E♭ - F - G - A♭ - B♭ - C
Phrygian C - D♭ - E♭ - F - G - A♭ - B♭ - C
Locrian C - D♭ - E♭ - F - G♭ - A♭ - B♭ - C

Table 3: Modes with C as root arranged in terms of brightness

Rearranging the representation on the left to the one on the right gives a neat visualisation of the modes in which at each step we flat one note at a time.

This way of arranging modes also makes more musical sense since each step of the way, 6 of the 7 notes remain the same and the one changed note provides a minimum delta of musical (or emotional) difference.

<aside> 💡 This theory places Lydian above Major in terms of brightness which is not an unusual notion. Refer to modal theory or George Russell’s amazing book Lydian Chromatic Concept of Tonal Organization for more details

</aside>


Formalising the idea

Let’s ignore the centuries of trial and error it took us to arrive at this neat theory and condense it down to a set of very fundamental transformations.

We need to define a few things first.

  1. A scale can be any subset of the chromatic scale
  2. We will only be considering scales of size 7
  3. A “well behaved” scale has intervallic distances not greater than 2 i.e. each subsequent note in the scale must be at most a whole tone away
  4. A “well behaved” scale does not have consecutive semitones i.e. we can’t have three consecutive chromatic notes