Music Theory and Composition Unit 4 ReviewTriads and Seventh Chords

Key Concepts and Definitions

• Triads consist of three notes stacked in thirds (root, third, and fifth) and form the basic building blocks of harmony
• Seventh chords add an additional third above the triad (root, third, fifth, and seventh) creating a richer harmonic texture
• Chord inversions rearrange the order of notes in a chord, with a note other than the root in the bass (first inversion has the third in the bass, second inversion has the fifth)
• Harmonic functions describe the role of chords within a key (tonic, subdominant, and dominant) and how they relate to each other
• Diatonic chords are built using only notes from the corresponding major or minor scale, while chromatic chords include notes outside the scale
• Chord progressions are sequences of chords that create a sense of musical direction and tension/resolution
• Cadences are specific chord progressions that provide a sense of ending or punctuation in a musical phrase (authentic, plagal, half, and deceptive)

Triad Structure and Types

• Major triads have a major third and perfect fifth above the root (C-E-G) and sound bright and stable
• Minor triads have a minor third and perfect fifth above the root (C-Eb-G) and sound darker and more melancholic
• Diminished triads have a minor third and diminished fifth above the root (C-Eb-Gb) and sound tense and unstable
• Augmented triads have a major third and augmented fifth above the root (C-E-G#) and sound exotic and unresolved
• Triads can be built on any scale degree in major or minor keys
  • In major keys: I, IV, and V are major; ii, iii, and vi are minor; vii° is diminished
  • In minor keys: i and iv are minor; III, VI, and VII are major; ii° and vii° are diminished
• Triads form the foundation for more complex chords and harmonic structures

Seventh Chord Basics

• Seventh chords are formed by adding a seventh above the triad (root, third, fifth, seventh)
• Major seventh chords have a major triad and a major seventh (C-E-G-B) and sound rich and sophisticated
• Dominant seventh chords have a major triad and a minor seventh (C-E-G-Bb) and sound strong and tension-building
• Minor seventh chords have a minor triad and a minor seventh (C-Eb-G-Bb) and sound smooth and jazzy
• Half-diminished seventh chords (also called minor 7 flat 5) have a diminished triad and a minor seventh (C-Eb-Gb-Bb) and sound dark and complex
• Diminished seventh chords have a diminished triad and a diminished seventh (C-Eb-Gb-Bbb) and sound highly dissonant and unstable
• Seventh chords add harmonic depth and variety to compositions

Chord Inversions and Voicings

• Chord inversions rearrange the order of notes in a chord, with a note other than the root in the bass
  • First inversion has the third in the bass (C-E-G becomes E-G-C)
  • Second inversion has the fifth in the bass (C-E-G becomes G-C-E)
  • Third inversion (for seventh chords) has the seventh in the bass (C-E-G-B becomes B-C-E-G)
• Inversions provide smoother bass lines and voice leading between chords
• Voicings refer to the specific arrangement of notes within a chord (close, open, drop)
  • Close voicings have the notes clustered together (C-E-G)
  • Open voicings spread the notes out over a wider range (C-G-E)
  • Drop voicings omit certain notes or rearrange them (C-G-Bb-E for a C7 drop 2 voicing)
• Different voicings can dramatically change the texture and emotional impact of a chord

Harmonic Functions and Progressions

• Harmonic functions describe the role of chords within a key
  • Tonic (I) provides a sense of stability and resolution
  • Subdominant (IV) adds contrast and movement away from the tonic
  • Dominant (V) creates tension and drives the progression back to the tonic
• Common chord progressions in major keys include:
  • I-IV-V-I (authentic cadence)
  • I-vi-IV-V (pop progression)
  • ii-V-I (jazz turnaround)
• Common chord progressions in minor keys include:
  • i-iv-V-i (minor authentic cadence)
  • i-VI-III-VII (descending thirds)
  • i-v-i (minor plagal cadence)
• Chord progressions create a sense of direction and emotional arc in a composition

Practical Applications in Composition

• Use triads and seventh chords as the foundation for harmonic structure in compositions
• Experiment with different chord types (major, minor, diminished, augmented) to create varied emotional effects
• Use inversions to create smooth bass lines and voice leading between chords
• Vary chord voicings to add texture and interest to harmonic progressions
• Use common chord progressions as a starting point, then modify or extend them to create unique harmonic sequences
• Analyze the harmonic structure of existing compositions to understand how triads and seventh chords are used effectively
• Practice improvising and composing with triads and seventh chords to internalize their sound and function

Common Mistakes and How to Avoid Them

• Parallel fifths and octaves occur when two voices move in the same direction and interval, creating an undesirable effect
  • To avoid, use contrary motion or have one voice remain stationary while the other moves
• Doubling leading tones or tendency tones can create awkward voice leading and resolutions
  • To avoid, double the root, fifth, or third of the chord instead
• Spacing chords too widely or too narrowly can result in an unbalanced or muddy sound
  • To avoid, aim for a balance of close and open voicings, and ensure that the chord tones are evenly distributed
• Overusing one chord type or progression can make a composition sound repetitive or predictable
  • To avoid, vary the chord types, inversions, and progressions throughout the piece
• Neglecting to consider the harmonic rhythm (rate of chord changes) can result in a static or disjointed composition
  • To avoid, vary the duration of chords and use harmonic rhythm to create a sense of forward motion and phrasing

Practice Exercises and Examples

• Identify and label triads and seventh chords in various keys (e.g., C major, A minor, F# major)
• Write out all inversions of a given triad or seventh chord (e.g., first, second, and third inversions of a G dominant seventh chord)
• Harmonize a simple melody using triads and seventh chords, focusing on smooth voice leading and appropriate chord choices
• Analyze the harmonic structure of a short composition, identifying the chord types, inversions, and functions
• Compose a 4-8 measure phrase using a specific chord progression (e.g., I-vi-ii-V in D major), experimenting with different voicings and inversions
• Transcribe the harmony of a short excerpt from a favorite song, identifying the triads and seventh chords used
• Practice improvising over a given chord progression, using triads and seventh chords as the basis for melodic and harmonic ideas