Music Theory and Composition

🎶Music Theory and Composition Unit 5 – Diatonic Harmony & Voice Leading

Diatonic harmony forms the backbone of Western music, using chords and progressions within a single key. It's built on triads - three-note chords stacked in thirds - and follows predictable patterns of tension and resolution. Understanding these patterns helps musicians create effective chord progressions and melodies. Voice leading is the art of smoothly connecting chords, ensuring each part moves logically and independently. This technique creates coherent harmonies and avoids awkward leaps or parallel motion. Mastering voice leading allows composers to craft more sophisticated and engaging music, balancing individual line interest with overall harmonic structure.

Key Concepts in Diatonic Harmony

  • Diatonic harmony refers to the use of chords and progressions within a single key or scale
  • Triads are the basic building blocks of diatonic harmony consisting of three notes stacked in thirds (root, third, and fifth)
  • Diatonic chords are built on each degree of the major or minor scale using only notes from that scale
  • The tonic chord (I) represents the home key and provides a sense of resolution and stability
  • Dominant chords (V) create tension and drive the harmony forward often resolving to the tonic
  • Subdominant chords (IV) provide contrast and movement away from the tonic
  • Diatonic progressions follow the natural tendencies and relationships between chords within a key
  • Cadences are specific chord progressions that provide closure or punctuation at the end of phrases (authentic, plagal, deceptive, half)

Chord Construction and Progressions

  • Triads can be major, minor, diminished, or augmented depending on the quality of the intervals between the notes
  • Seventh chords are formed by adding a fourth note to a triad a third above the fifth (major seventh, minor seventh, dominant seventh, half-diminished seventh, fully-diminished seventh)
  • Roman numerals are used to represent chords built on each scale degree (I, ii, iii, IV, V, vi, vii°)
  • Uppercase numerals indicate major chords while lowercase numerals indicate minor chords
  • The most common diatonic progressions include I-IV-V, I-vi-IV-V, and ii-V-I
  • Chord inversions occur when the bass note is not the root of the chord (first inversion, second inversion)
    • First inversion chords have the third in the bass and are labeled with a superscript 6 (I6)
    • Second inversion chords have the fifth in the bass and are labeled with a superscript 64 (I64)
  • Harmonic rhythm refers to the rate at which chords change often aligning with the meter and phrase structure

Voice Leading Principles

  • Voice leading involves the smooth and logical movement of individual voices or parts within a chord progression
  • The goal is to create a sense of independence and coherence between the voices while avoiding awkward leaps or parallel motion
  • Common voice leading guidelines include:
    • Resolve tendency tones (leading tone resolves up to tonic, seventh resolves down)
    • Avoid parallel fifths and octaves between voices
    • Use contrary motion when possible (voices moving in opposite directions)
    • Keep common tones between chords in the same voice
    • Resolve dissonant intervals (sevenths, seconds) to consonant intervals (thirds, sixths)
  • Passing tones and neighbor tones are non-chord tones used to connect chord tones and create smooth melodic lines
  • Suspensions occur when a note is held over from the previous chord creating a temporary dissonance before resolving

Analyzing Diatonic Harmony in Music

  • Harmonic analysis involves identifying chords and progressions in a musical score or recording
  • The first step is to determine the key and scale of the piece (major or minor)
  • Chords are labeled using Roman numerals to show their relationship to the tonic
  • Non-chord tones and embellishments are identified and labeled (passing tones, neighbor tones, suspensions, etc.)
  • Cadences and phrase endings are marked and classified (authentic, plagal, deceptive, half)
  • Modulations to new keys are identified by changes in the diatonic chord progressions and accidentals
  • Harmonic rhythm and chord inversions are noted to understand the pacing and voice leading of the progression
  • Analysis can reveal patterns, form, and compositional techniques used by the composer or songwriter

Common Compositional Techniques

  • Pedal points involve sustaining a single note (usually the tonic or dominant) while the other voices move around it creating tension and release
  • Sequences are repetitions of a melodic or harmonic pattern at different pitch levels often used for development and variation
  • Secondary dominants are chords borrowed from outside the key that temporarily tonicize a diatonic chord (V/V, V/ii, V/vi)
  • Modulation is the process of changing keys within a piece often using a pivot chord that belongs to both the old and new key
  • Harmonic substitution involves replacing an expected chord with a different chord that serves a similar function (tritone substitution, modal interchange)
  • Diatonic seventh chords can be used to add color and complexity to progressions (ii7, IV7, vi7)
  • Suspensions and retardations create dissonance and resolution by delaying the expected chord tone
  • Passing and neighbor chords are brief non-diatonic chords used to connect diatonic chords and create smooth voice leading

Practical Applications in Songwriting

  • Understanding diatonic harmony allows songwriters to create chord progressions that effectively convey emotions and support the melody
  • The choice of key and mode (major or minor) sets the overall mood and character of the song
  • Chord progressions can be used to create tension, release, and momentum in different sections of the song (verse, chorus, bridge)
  • Cadences are used to provide closure and punctuation at the end of phrases and sections
  • Harmonic rhythm can be varied to create interest and align with the lyrical phrasing and meter
  • Inversions and voice leading techniques can be used to create smooth transitions between chords and sections
  • Modulation can be used to change keys and create contrast or a sense of development within the song
  • Diatonic harmony can be combined with other compositional techniques (pedal points, sequences, secondary dominants) to add depth and complexity to the songwriting

Exercises and Ear Training

  • Practice identifying and singing the scale degrees and diatonic triads in major and minor keys
  • Analyze the chord progressions in popular songs and classical pieces to identify diatonic patterns and techniques
  • Write out the diatonic triads and seventh chords in various keys and practice playing them on an instrument
  • Practice harmonizing simple melodies using diatonic chords and proper voice leading techniques
  • Transcribe chord progressions from recordings and identify the key, chord qualities, and inversions used
  • Compose short chord progressions using diatonic chords and common patterns (I-IV-V, I-vi-IV-V, ii-V-I)
  • Practice identifying and singing intervals, triads, and seventh chords in isolation and within a harmonic context
  • Engage in call-and-response exercises with a partner singing diatonic chord progressions and cadences

Advanced Topics and Further Study

  • Chromatic harmony involves the use of chords and tones outside the diatonic scale creating more complex and colorful progressions
  • Modal harmony uses the seven diatonic modes (Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian) as the basis for chord construction and progression
  • Neo-Riemannian theory explores the relationships between triads and transformations between them (parallel, relative, leading-tone exchange)
  • Schenkerian analysis is a method of understanding the deep structure and prolongations of tonal music using techniques like reduction and voice-leading graphs
  • Set theory and twelve-tone techniques are used in post-tonal and atonal music to organize and analyze pitch collections and series
  • Jazz harmony builds on diatonic harmony with the use of extended chords, alterations, and substitutions to create more complex and colorful progressions
  • Counterpoint is the art of combining multiple independent melodic lines to create a harmonically coherent texture
  • Further study can include exploring the harmonic languages of specific composers, genres, or historical periods (Baroque, Classical, Romantic, Impressionistic, Contemporary)


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© 2024 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.