🎹Tonal Composition Unit 2 – Diatonic Harmony: Triads & Seventh Chords

Key Concepts

• Diatonic harmony focuses on chords built from the notes of a particular key or scale
• Triads are three-note chords consisting of a root, third, and fifth
• Seventh chords add a fourth note, the seventh, to a triad
• Chord progressions are sequences of chords that create harmonic movement
• Voice leading is the smooth movement of individual voices or parts within a chord progression
• Harmonic analysis involves identifying chords and their functions within a musical context
• Understanding diatonic harmony is essential for composing and analyzing tonal music
• Common pitfalls include parallel fifths, octaves, and improper voice leading

Triad Basics

• Triads are built by stacking thirds on top of a root note
• The quality of a triad depends on the intervals between its notes
  • Major triads have a major third and a perfect fifth (C-E-G)
  • Minor triads have a minor third and a perfect fifth (C-Eb-G)
  • Diminished triads have a minor third and a diminished fifth (C-Eb-Gb)
  • Augmented triads have a major third and an augmented fifth (C-E-G#)
• Triads can be inverted, meaning the root is not always the lowest note
  • First inversion has the third as the lowest note (E-G-C)
  • Second inversion has the fifth as the lowest note (G-C-E)
• Triads built on each degree of a major scale have specific qualities (I-maj, ii-min, iii-min, IV-maj, V-maj, vi-min, vii°-dim)
• Triads built on each degree of a minor scale also have specific qualities (i-min, ii°-dim, III-maj, iv-min, V-maj, VI-maj, VII-maj)

Seventh Chord Foundations

• Seventh chords are formed by adding a seventh to a triad
• The quality of the seventh determines the overall quality of the chord
  • Major seventh chords have a major triad and a major seventh (Cmaj7: C-E-G-B)
  • Dominant seventh chords have a major triad and a minor seventh (C7: C-E-G-Bb)
  • Minor seventh chords have a minor triad and a minor seventh (Cmin7: C-Eb-G-Bb)
  • Half-diminished seventh chords have a diminished triad and a minor seventh (Cø7: C-Eb-Gb-Bb)
  • Fully diminished seventh chords have a diminished triad and a diminished seventh (C°7: C-Eb-Gb-Bbb)
• Seventh chords can also be inverted, with the root, third, fifth, or seventh as the lowest note
• Seventh chords built on each degree of a major scale have specific qualities (Imaj7, ii7, iii7, IVmaj7, V7, vi7, viiø7)
• In minor keys, the seventh chords on each scale degree are i7, iiø7, III+7, iv7, V7, VImaj7, VII7

Chord Progressions

• Chord progressions provide harmonic structure and movement in tonal music
• Common chord progressions in major keys include I-IV-V, I-vi-IV-V, and ii-V-I
• In minor keys, common progressions include i-iv-V, i-VI-III-VII, and ii°-V-i
• Cadences are specific chord progressions that provide a sense of resolution or tension
  • Authentic cadences move from V to I (perfect authentic cadence if the root is in the soprano)
  • Plagal cadences move from IV to I
  • Deceptive cadences move from V to vi
  • Half cadences end on V
• Chord progressions can be used to establish a key, modulate to a new key, or create harmonic interest

Voice Leading

• Voice leading is the art of smoothly connecting chords by considering the movement of individual voices
• The goal is to create a sense of independence and coherence among the voices
• Avoid parallel fifths and octaves between any two voices
• Strive for contrary and oblique motion when possible
• Use common tones and stepwise motion to connect chords smoothly
• Resolve tendency tones properly (leading tone resolves to tonic, seventh resolves down by step)
• Consider the range and tessitura of each voice to maintain a balanced texture

Harmonic Analysis

• Harmonic analysis involves labeling chords and understanding their functions within a musical context
• Use Roman numerals to label chords based on their scale degree (I, ii, iii, IV, V, vi, vii°)
• Indicate chord quality using uppercase for major, lowercase for minor, and symbols for diminished (°) and augmented (+)
• Identify non-chord tones, such as passing tones, neighbor tones, suspensions, and anticipations
• Analyze chord progressions, cadences, and modulations to understand the overall harmonic structure
• Consider the relationship between melody and harmony, and how they interact to create musical meaning

Practical Applications

• Apply diatonic harmony concepts when composing original music
• Use chord progressions and voice leading techniques to create effective harmonizations of melodies
• Analyze existing tonal compositions to understand their harmonic structure and compositional techniques
• Practice identifying chords and progressions by ear to develop aural skills
• Experiment with different chord voicings and inversions to create varied textures and colors
• Use harmonic analysis to make informed interpretive decisions when performing tonal music
• Incorporate diatonic harmony concepts into improvisation and arranging

Common Pitfalls

• Avoid parallel fifths and octaves between any two voices, as they can create a lack of independence
• Be mindful of voice crossing, which occurs when a lower voice moves above a higher voice (or vice versa)
• Ensure proper resolution of tendency tones, such as the leading tone and seventh
• Avoid doubling tendency tones, especially the leading tone, in chord voicings
• Be cautious when using inversions, as they can sometimes create awkward voice leading or weak progressions
• Avoid overusing dominant seventh chords, as they can create a sense of harmonic stagnation
• Remember to consider the harmonic rhythm, or the rate at which chords change, to maintain a sense of balance and forward motion