Music Theory

Chapter 4 : Diatonic Chords in Major and Minor Keys

Intro

• Diatonic : chords using only those notes found in the key signature (“of the tonic”)

• Altered/Chromatic : those using notes not in the scale (we will study these later…)

• The rest of this chapter will focus on identifying and spelling diatonic chords

The Minor Scale

• The minor scale(s) pose problems for the theorist/performer

• Three types of minor scales? Differences?• Composers did not have three independent

scales from which to choose• Discuss scales degrees and applicability of

those degrees

The Minor Scale ; A few general ‘rules’

• The most graceful thing for ^6 and ^7 is to ascend by step, and for v6 and v7 to descend by step (Ex. 4-2)

• If 6 or 7 is left by leap instead of step, there will be an eventual stepwise goal for that scale degree, and 6/7 will be raised or unaltered according to the direction of that goal (Ex. 4-3)

• In some cases, v6 and v7 lead upward (Ex. 4-4)• In other cases, v6 and ^7 appear together, providing the

harmonic minor scale (Ex. 4-5)• The ultimate guiding rule is usually harmonic• As we will learn, most harmony in minor conforms to the

harmonic minor scale

Checkpoint

• What is the term for chords that contain no notes outside of the scale? What about chords that do contain such notes?

• Individual lines in tonal music tend to conform most closely to which of the three traditional minor scales?

• Name the five common seventh-chord types.

Diatonic Triads in Major

• Triads may be constructed on any degree of the major scale (review scale degrees)

• Diatonic triads• We will use roman numerals instead of Arabic

numerals to distinguish triadsTriad Type Roman numeral Example

Major Uppercase V

Minor Lowercase vi

Diminished Lowercase with a ° vii°

Augmented Uppercase with a + III+

Diatonic Triads

Diatonic Triads in Major Key

Major I, IV, and V

Minor Ii, iii, vi

Diminished vii°

Augmented none

MEMORIZE!

Diatonic Triads in Minor

• Construction of triads in minor is more complicated than major

• 6 and 7 are variable• More diatonic triads are possible in minor• Seven diatonic triads appear more than others

Diatonic Triads in minor

Major III, V, and VI

Minor i, and iv

Diminished Ii° and vii°

Augmented none

MEMORIZE!

Checkpoint

• In a major key, which triads are minor?• In a minor key, which triads are major?• The triads on which two scale degrees are the

same type in both major and minor?• Which of the four triad types occurs least

often in tonal music?

*self-test 4-1

Diatonic Seventh Chords in Major• Diatonic triads in major can also include 7th above the root

Seventh-Chord type Roman Numeral Example

Major seventh Uppercase with M7 IM7

Major-minor seventh Uppercase with a 7 V7

Minor seventh Lowercase with a 7 vi7

Half-diminished seventh Lowercase with a Ø7 iiØ7

Diminished seventh Lowercase with a Vii°7

Diatonic Seventh-Chords in Major

M7 IM7, and IVM7

Mm7 V7

m7 Ii7, iii7, vi7

Ø7 viiØ7

°7 none

MEMORIZE!

Diatonic Seventh-Chords in Minor

• There are sixteen possible diatonic seventh chords in minor (6&7)

Diatonic Seventh-Chords

Common Diatonic Seventh Chords in Minor

M7 IIIM7, and VIM7

Mm7 V7

m7 i7 and iv7

Ø7 iiØ7

°7 Vii°7

MEMORIZE!

Checkpoint

• Most of the five common seventh-chord types appear diatonically in both major and minor. Which one does not?

• Does the m7 chord occur on more scale steps in minor than in major?

• The seventh chords on most scale steps are different qualities in major and minor. Which scale step is the exception to this?

*self-test 4-2