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

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)