Chord substitution is a powerful tool in jazz and modern guitar music, allowing musicians to replace standard chords with alternative ones to create fresh harmonic colors and maintain listener interest. Voice leading is the practice of moving individual notes (voices) within chords in the smoothest possible way, often by preserving common tones between adjacent chords. Together, these concepts enable seamless harmonic progressions and sophisticated arrangements.
- Chord substitution replaces a chord with another that shares shared tones or functions.
- Voice leading moves chord tones stepwise, or keeps some tones unchanged, for smoother transitions.
- Used extensively in jazz to add harmonic complexity and variation.
- Enhances improvisation, arrangement, and composition on guitar.
Chord Substitution
Chord substitution involves replacing a given chord with another that serves a similar harmonic function but provides a different sound. This is commonly done to add variety and sophistication to progressions.
- Common-Tone Substitution: The new chord shares one or more notes with the original chord.
- Functional Substitution: The substitute chord has a similar role in the progression (e.g., replacing a dominant chord with a tritone substitute).
- Diatonic Substitution: Using another chord from the same key to replace the original chord.
Common-tone, functional, and diatonic substitution are typical chord substitution methods.
Common Examples:
- Tritone substitution (e.g., replacing G7 with Db7).
- Replacing a major chord with a vi minor chord (I → vi).
- Using relative minor/major substitutions (C → Am).
Tritone substitution is commonly used for dominant 7 chords.
Exercise: Given the chord progression Cmaj7 - Am7 - Dm7 - G7, suggest possible chord substitutions for Am7 and G7.
Voice Leading
Voice leading is the technique of connecting chords so that each individual note (voice) moves as smoothly and logically as possible, often by moving by step (half or whole tone) or staying on the same note.
- Common Tones: Notes that don’t change between chords.
- Stepwise Motion: Notes move by smallest possible intervals, usually half or whole steps.
- Contrary Motion: Some voices move in opposite directions, balancing the sound.
Good voice leading minimizes note movement and preserves common tones.
Benefits of Voice Leading:
- Creates smooth, professional-sounding progressions.
- Makes chord changes easier to play.
- Enhances melodic interest within chords.
Voice leading prioritizes smooth movement of individual notes.
Exercise: For the chords Cmaj7 (C-E-G-B) and Am7 (A-C-E-G), show the voice leading of each note when moving between the two chords.
Combining Chord Substitution and Voice Leading
When you substitute chords, strong voice leading ensures the progression still sounds smooth and connected, despite the changes.
- Substitutions that share tones or similar notes often allow the best voice leading.
- Even complex substitutions can sound natural with smart voice leading.
- Used by jazz guitarists to create fluid, harmonically rich progressions.
Voice leading maintains smooth transitions during chord substitutions.
Example: In jazz, a G7 chord might be substituted with Db7 (a tritone substitution). Voice leading between these chords involves moving the shared notes minimally for a seamless transition.
Exercise: How would you apply voice leading when substituting G7 with Db7 in the progression Cmaj7 - G7 - Cmaj7?
Conclusion
Chord substitution refreshes harmonies, while voice leading preserves smoothness and coherence. Together they expand the expressive potential of guitar progressions, especially in jazz.
- Chord substitution replaces chords for new harmonic color; common types include tritone, diatonic, and common-tone substitutions.
- Voice leading moves chord tones smoothly, preserving common notes or shifting by step for seamless transitions.
- Mastery of both concepts enables sophisticated, fluid harmonic progressions on guitar.