Harmonic progression forms the backbone of Western tonal music, shaping how chords flow and interact. It's key to creating cohesive, expressive compositions that establish a tonal center and build tension and resolution throughout a piece.

Understanding harmonic progression helps musicians craft compelling musical narratives. From basic triads to complex chromatic progressions, these chord sequences create the emotional journey of a song, guiding listeners through moments of stability, tension, and release.

Harmonic progression fundamentals

• Harmonic progression refers to the sequence of chords used in a musical composition and forms the foundation of Western tonal music
• Understanding harmonic progressions is essential for creating cohesive and expressive musical compositions and arrangements
• Harmonic progressions establish the tonal center and create a sense of tension and resolution throughout a piece

Chords in harmonic progressions

• Chords are the building blocks of harmonic progressions and are formed by combining three or more notes played simultaneously
• Triads, consisting of a root, third, and fifth, are the most basic and commonly used chords in harmonic progressions (major, minor, diminished)
• Seventh chords, such as dominant seventh and minor seventh chords, add additional tension and color to harmonic progressions
• Inversions of chords, where notes other than the root are in the bass, provide variety and smooth voice leading in harmonic progressions

Cadences and phrase endings

• Cadences are specific chord progressions that provide a sense of closure or resolution at the end of a musical phrase or section
• Perfect authentic cadence (PAC) is the most conclusive and features a dominant to tonic progression (V-I) with both chords in root position
• Imperfect authentic cadence (IAC) is similar to a PAC but has the tonic chord in an inversion, creating a slightly less conclusive ending
• Plagal cadence, also known as the "Amen" cadence, moves from the subdominant to the tonic (IV-I) and has a softer, more relaxed resolution
• Half cadence ends on the dominant chord (V), creating a sense of incompleteness and anticipation for the next phrase

Tonic and dominant relationships

• The tonic chord (I) represents the home key or tonal center of a piece and provides a sense of stability and resolution
• The dominant chord (V) creates tension and a strong pull towards the tonic, making it a crucial element in establishing harmonic motion
• The dominant-tonic relationship is the most fundamental and powerful in tonal harmony, often used in cadences and key establishing moments
• The subdominant chord (IV) serves as a predominant, leading towards the dominant and helping to establish the tonic-dominant relationship

Diatonic harmonic progressions

• Diatonic harmonic progressions use chords built exclusively from notes within the prevailing key, creating a sense of unity and stability
• Diatonic chords are triads or seventh chords constructed on each degree of the major or minor scale
• Diatonic progressions often follow established patterns and conventions, such as the circle of fifths progression (I-IV-vii°-iii-vi-ii-V-I)

Primary chords (I, IV, V)

• The primary chords, also known as the tonic (I), subdominant (IV), and dominant (V), are the most essential chords in a diatonic progression
• These chords form the backbone of tonal harmony and are used to establish the key, create tension and resolution, and provide a sense of direction
• The I chord represents stability, the IV chord provides contrast and movement away from the tonic, and the V chord creates tension and a strong pull back to the tonic
• Primary chord progressions, such as I-IV-V-I or I-V-I, are common in various musical styles and form the basis for more complex harmonic structures

Secondary chords (ii, iii, vi)

• Secondary chords, also called auxiliary or intermediate chords, are the remaining diatonic chords built on scale degrees 2, 3, and 6
• These chords provide additional harmonic color, variety, and smooth transitions between the primary chords
• The supertonic chord (ii) often functions as a subdominant substitute, leading to the dominant chord (ii-V-I)
• The mediant chord (iii) and submediant chord (vi) can be used as substitutes for the tonic chord, creating a sense of temporary departure from the home key (I-iii-IV-I or I-vi-IV-V)

Diatonic chord progressions

• Diatonic chord progressions combine primary and secondary chords to create more interesting and varied harmonic movements within a key
• Common diatonic chord progressions include I-vi-IV-V, I-ii-V-I, and I-iii-vi-ii-V-I, each with its own unique character and emotional effect
• Diatonic progressions can be extended by using seventh chords, inversions, and substitutions, adding depth and sophistication to the harmony
• Mastering diatonic chord progressions is essential for understanding and analyzing more complex harmonic structures in tonal music

Non-diatonic harmonic progressions

• Non-diatonic harmonic progressions introduce chords from outside the prevailing key, creating a sense of tension, surprise, or emotional intensity
• These progressions can be used to temporarily depart from the established key, add harmonic color, or modulate to a new key
• Non-diatonic chords are often used strategically to enhance the overall musical narrative and create memorable moments in a composition

Secondary dominants

• Secondary dominants are chords that temporarily tonicize a diatonic chord other than the tonic, acting as a dominant chord in relation to the target chord
• These chords are usually formed by raising the third of a diatonic chord, creating a temporary leading tone and a sense of increased tension and resolution
• Common secondary dominants include V/V (read as "five of five"), V/IV, and V/ii, each resolving to its respective target chord
• Secondary dominants add harmonic interest, variety, and a sense of movement within a diatonic progression (I-V/V-V-I or I-ii-V/V-V-I)

Borrowed chords

• Borrowed chords, also known as modal mixture, are chords borrowed from the parallel major or minor key to add emotional depth and harmonic color
• In a major key, borrowing chords from the parallel minor can create a sense of sadness, introspection, or drama (I-bVI-bVII-I)
• In a minor key, borrowing chords from the parallel major can create a sense of brightness, hope, or resolution (i-IV-V-i)
• Commonly borrowed chords include the flat sixth (bVI), flat seventh (bVII), and major subdominant (IV) in a minor key

Chromatic chord progressions

• Chromatic chord progressions use chords that contain notes outside the diatonic scale, creating a sense of tension, instability, and emotional complexity
• These progressions often involve chromatic mediant relationships, where chords are related by a third and share a common tone (I-bIII-bVI-I or I-III-vi-I)
• Chromatic progressions can also include altered chords, such as augmented sixths or Neapolitan sixths, which create striking harmonic colors and tensions
• Chromatic progressions are often used in musical genres such as jazz, romantic-era classical music, and film scores to evoke strong emotions and create dramatic effects

Harmonic rhythm and pacing

• Harmonic rhythm refers to the rate at which chords change within a musical passage, affecting the sense of movement, stability, and emotional intensity
• The pacing of harmonic changes can be used to create tension, release, and forward motion in a composition
• Varying the harmonic rhythm and pacing can add interest, depth, and structural clarity to a musical work

Strong vs weak beats

• In most musical meters, certain beats are perceived as stronger or more accented than others, creating a hierarchy of strong and weak beats
• Placing chord changes on strong beats (downbeats) creates a sense of stability and resolution, while placing them on weak beats creates a sense of tension and forward motion
• Harmonic rhythm often aligns with the prevailing meter, with chord changes occurring on strong beats (I-I-IV-IV-V-V-I-I in 4/4 time)
• Syncopated harmonic rhythms, where chord changes occur on weak beats or offbeats, can create a sense of excitement, anticipation, or rhythmic interest

Harmonic rhythm variations

• Varying the harmonic rhythm within a composition can create a sense of ebb and flow, highlight important structural moments, or reflect changes in the musical narrative
• Prolonging a chord or delaying a resolution can create a sense of tension, anticipation, or emotional intensity
• Accelerating the harmonic rhythm can create a sense of urgency, excitement, or instability, while slowing it down can create a sense of calm, reflection, or resolution
• Composers often use harmonic rhythm variations in conjunction with melodic, rhythmic, and textural changes to create a cohesive and expressive musical work

Pacing and forward motion

• The pacing of harmonic changes can be used to create a sense of direction, growth, and resolution in a musical composition
• Gradual harmonic movements, such as the circle of fifths progression, create a sense of smooth and inevitable forward motion
• Abrupt or unexpected harmonic changes can create a sense of surprise, tension, or emotional intensity, propelling the music forward
• Balancing stability and instability, tension and release, and predictability and surprise in the pacing of harmonic changes is essential for creating engaging and expressive music

Voice leading in harmonic progressions

• Voice leading refers to the way individual melodic lines or voices move from one chord to another in a harmonic progression
• Effective voice leading ensures smooth, logical, and aesthetically pleasing transitions between chords, enhancing the overall coherence and expressiveness of the music
• Proper voice leading techniques help to maintain the independence and integrity of each voice while creating a sense of harmony and unity

Smooth voice leading principles

• Move each voice by the smallest possible interval when transitioning between chords, preferring stepwise motion or common tones
• Avoid large leaps in individual voices, especially in the bass, as they can create a sense of disconnection or instability
• Maintain the independence of voices by avoiding parallel motion in perfect intervals (fifths and octaves), which can create a sense of blending or loss of individuality
• Strive for contrary motion between voices, especially between the bass and the upper voices, to create a sense of balance and counterpoint

Common voice leading patterns

• The 7-6 suspension is a common voice leading pattern in which the seventh of a chord resolves downward by step to the sixth of the next chord, creating a sense of tension and resolution (V7-I)
• The 4-3 suspension involves the fourth of a chord resolving downward by step to the third of the next chord, often used in plagal cadences (IV-I)
• The leading tone resolves upward by step to the tonic in authentic cadences (vii°-I or V7-I), creating a strong sense of resolution and finality
• Passing tones and neighbor tones can be used to connect chords smoothly, creating a sense of melodic and harmonic continuity

Avoiding parallel fifths and octaves

• Parallel fifths and octaves occur when two voices move in the same direction by a perfect fifth or octave, creating a sense of blending or loss of independence
• To avoid parallel fifths and octaves, use contrary motion, oblique motion (one voice moves while the other stays on the same note), or have one voice leap by a third or more
• Composers may choose to use parallel fifths or octaves intentionally for a specific musical effect, such as creating a sense of power, unity, or ancient/medieval sound
• Developing an understanding of proper voice leading principles and techniques is essential for creating effective and expressive harmonic progressions

Harmonizing melodies

• Harmonizing melodies involves selecting and applying chords to support and enhance a given melodic line
• Effective harmonization requires an understanding of the melody's structure, phrasing, and emotional content, as well as knowledge of harmonic progressions and voice leading principles
• The goal of harmonization is to create a cohesive and expressive musical work that combines the melodic and harmonic elements in a meaningful and aesthetically pleasing way

Identifying chord tones

• To harmonize a melody, begin by identifying the chord tones (root, third, fifth, and seventh) in the melodic line
• Chord tones are the notes that are most stable and consonant with the underlying harmony and can help guide the choice of chords
• Non-chord tones, such as passing tones, neighbor tones, and suspensions, can be used to add melodic interest and smooth transitions between chords
• Analyzing the melodic structure and identifying chord tones helps to create a strong and logical harmonic foundation for the melody

Selecting appropriate chords

• When selecting chords to harmonize a melody, consider the key, the melodic structure, and the desired emotional effect
• Use primary chords (I, IV, V) to establish the key and create a sense of stability, and secondary chords (ii, iii, vi) to add variety and smooth transitions
• Employ non-diatonic chords, such as secondary dominants or borrowed chords, to create tension, surprise, or emotional intensity
• Consider the harmonic rhythm and pacing, ensuring that chord changes support the melodic phrasing and create a sense of forward motion

Creating accompaniments

• Once the chords have been selected, create an accompaniment that supports and enhances the melody and harmonic progression
• Accompaniment styles can range from simple block chords to more complex arpeggiated or contrapuntal patterns, depending on the musical genre and desired effect
• Use effective voice leading techniques to ensure smooth and logical transitions between chords in the accompaniment
• Consider the texture, dynamics, and rhythmic patterns of the accompaniment, ensuring that it complements and balances the melody without overpowering it

Modulation and key changes

• Modulation is the process of changing from one key to another within a musical composition, creating a sense of variety, contrast, and emotional development
• Key changes can be used to reflect changes in the musical narrative, to create a sense of tension and resolution, or to explore different tonal colors and moods
• Effective modulations require a smooth and logical transition between keys, often involving the use of common chords, pivot chords, or chromatic harmony

Common modulation techniques

• Common chord modulation involves using a chord that is common to both the original key and the new key as a pivot point for the modulation (C major to G major using the D minor chord)
• Chromatic modulation involves using chromatic chords, such as secondary dominants or altered chords, to create a smooth transition between keys (C major to E major using the B7 chord)
• Phrase modulation involves ending a phrase in the original key and beginning the next phrase in the new key, often with a direct or abrupt transition (C major to A minor)
• Sequential modulation involves moving through a series of keys by transposing a musical idea or progression by a consistent interval (C major to D major to E major)

Pivot chord modulations

• A pivot chord is a chord that belongs to both the original key and the new key and serves as a bridge between the two tonalities
• To execute a pivot chord modulation, identify a chord that is common to both keys and use it as a transition point, reinterpreting its function in the new key
• For example, in a modulation from C major to G major, the D minor chord (ii in C major) can be reinterpreted as the ii chord in G major, serving as the pivot chord
• Pivot chord modulations create a sense of smoothness and continuity, as the listener's ear is gradually led from one key to another

Direct modulations

• A direct modulation, also known as a phrase modulation, involves ending a phrase in one key and beginning the next phrase in a new key without any preparation or transition
• Direct modulations create a sense of surprise, contrast, or emotional shift, as the listener is abruptly transported to a new tonal center
• For example, a piece in C major can directly modulate to A minor by ending a phrase on a C major chord and beginning the next phrase on an A minor chord
• Direct modulations are often used in musical genres such as pop, rock, and musical theater to create dramatic or unexpected key changes

Analyzing harmonic progressions

• Analyzing harmonic progressions involves identifying and interpreting the chords, key centers, and harmonic relationships within a musical composition
• Harmonic analysis helps musicians understand the structure, function, and emotional content of a piece, informing performance, interpretation, and composition
• There are several methods for analyzing harmonic progressions, each with its own set of symbols, terminology, and analytical focus

Roman numeral analysis

• Roman numeral analysis uses Roman numerals (I, ii, iii, IV, V, vi, vii°) to represent chords based on their scale degree and quality within a given key
• Uppercase Roman numerals (I, IV, V) denote major chords, while lowercase Roman numerals (ii, iii, vi) denote minor chords, and the diminished symbol (°) is used for diminished chords
• Inversions are indicated with figured bass symbols (I6, IV64) or by using a lowercase letter (Ib, IVc)
• Roman numeral analysis provides a clear and concise way to identify chords and their relationships within a key, making it easier to recognize common harmonic patterns and progressions

Functional harmony analysis

• Functional harmony analysis focuses on the role and behavior of chords within a harmonic progression, categorizing them as tonic (T), subdominant (S), or dominant (D) functions
• Tonic function chords (I, iii, vi) provide a sense of stability and resolution, while subdominant function chords (ii, IV) create a sense of departure or movement away from the tonic
• Dominant function chords (V, vii°) create tension and a strong pull back to the tonic,