Harmonic Progression

• Harmonic progression refers to the sequence in which chords are placed in a piece of music, creating a sense of direction and movement.
• This concept heavily relies on the tonal centre or key of a piece.
• Harmonic progressions are usually displayed using Roman numerals, with each numeral representing a chord's position within a key.
• An understanding of scale degrees is pivotal for writing and analysing harmonic progression.
• Frequently used progressions include I-IV-V (common in blues and rock) and ii-V-I (prevalent in jazz).
• The progression from V to I or V7 to I is called an authentic cadence, which effectuates a strong sense of resolution or closure.

Functional Harmony

• Functional Harmony is a theory developed to explain why certain harmonic progressions provoke specific emotional responses.
• In functional harmony, chords are classified into three main functions: Tonic (T), Subdominant (S), and Dominant (D).
• Tonic chords are the home base of a key, usually the first and last chord of a piece, and provide a sense of resolution and repose.
• Subdominant chords are transitioning chords that often lead away from the Tonic towards the Dominant.
• Dominant chords typically drive tension and expect resolution, usually resolving back to the Tonic. They are often the V or VII chord of a scale.

Cadences

• Cadences are musical punctuation marks; they create a sense of resolution or indicate the end of a phrase, section, or piece.
• There are several types of cadences including Perfect (Authentic), Imperfect (Half), Plagal, Deceptive, and Interrupted cadences.
• A Perfect Cadence (V-I or V7-I) sounds complete and is often used at the end of a piece.
• An Imperfect Cadence (any chord-V or V7) provides a degree of resolution but feels unfinished, pushing the music forward.
• A Plagal Cadence (IV-I), often called an 'Amen' cadence, is commonly heard at the end of hymns.
• A Deceptive Cadence (V-vi or V-VI) diverts expectations by resolving to a different chord than the anticipated Tonic, creating a surprising effect.
• An Interrupted Cadence also diverts from the standard progression, producing a sense of abrupt interruption, often used for dramatic effect.