A scale is a collection of intervals within an octave. Scales are used to construct melodies and derive chords.
A scale family is a scale collection made up of a parent scale and each of its modes (permutations of itself).
A parent scale is simply a scale that a scale family is named after.
A mode is a scale that has an identical interval sequence to its parent scale interval, but starts on a different scale degree, which serves as the mode’s root. A parent scale can also be referred to as a mode of its scale family.
Modes of C major scale:
- C D E F G A B (C Major) (also called C Ionian)
- D E F G A B C (D Dorian)
- E F G A B C D (E Phrygian)
- F G A B C D E (F Lydian)
- G A B C D E F (G Mixolydian)
- A B C D E F G (A Aeolian)
- B C D E F G A (B Locrian)
Scale Families
The following scale families are suitable for deriving chords from:
- Major (7 notes, 7 modes)
- Minor (7 notes, 7 modes)
- Harmonic Minor (7 notes, 7 modes)
- Harmonic Major (7 notes, 7 modes)
- Diminished (8 notes, 2 modes)
- Augmented (6 notes, 2 modes
- Wholetone (6 notes, 1 mode)
The terms mode and scale are often used synonymously.
The above 7 families make up a grand total of 33 scales that can be used to build chords from:
7 Note (24 scales):
Major Scale (Ionian)
Dorian
Phrygian
Lydian
Mixolydian
Aeolian
Locrian
Harmonic Minor
Locrian♮6
Ionian ♯5
Dorian ♯4
Mixolydian♭9♭13
Lydian ♯2
Ultralocrian
Melodic Minor
Dorian♭2
Lydian ♯5
Lydian♭7
Mixolydian♭13
Locrian♮9
Altered
Harmonic Major
Dorian♭5
Phrygian♭4
Lydian♭3
Mixolydian♭9
Lydian♯5♯2
Locrian°7
Septatonic Scales
Because septatonic scales (7 note scales) serve as the primary scales for deriving chords in Western Tonal Music, the musical alphabet and the naming convention for intervals has been built around them where each octave is divided by 7 steps which vary in size depending on the scale. Consequently, when considering hexatonic (6 notes) and octatonic (8 notes) scales, we tend to name intervals and chords while still using the naming conventions of 7 note scales.
6 Note Scales:
Whole Tone
Augmented
Inverted Augmented
8 Notes Scales:
Symmetrical Diminished
Symmetrical Dominant
Pentatonic Scales
Pentatonic scales contain 5 notes. While they do not serve as the source of chords, they are used prolifically in the constructing of melodies. They usually represent a subset of notes from a septatonic scale.
Rules for Deriving Reasonable Harmonic Structures
Scales Suitable for Deriving Harmony –
Reference:
- H = half = 1 semitone
- W = whole = 2 semitones
- WH = whole & a half = 3 semitones
Scale Rules:
- Must fit within 1 octave
- Only uses H, W, and WH
- H cannot be neighbors
- W & WH cannot be neighbors
- WH cannot be neighbors
- If a scale can follow these rules, it is a perfect candidate to build chords from.
C→G→D→A→E
