Harmony and Tonality

This section explains harmony and tonality within music, including: chords, triads and cadence.

Harmony refers to the combination of different musical notes played or sung simultaneously to produce a fuller, richer sound. Tonality relates to the organisation of pitches around a central note (tonic) to create a key or mode.

Chords and Triads

Chords: A chord is a group of three or more notes played together. Chords create the harmonic foundation of a piece of music.

Triads: A triad is the simplest type of chord, made up of three notes: the root, third, and fifth. For example, in C major, the triad consists of C (root), E (third), and G (fifth).

Dominant and Subdominant Chords

Dominant (V): The fifth chord in a key (e.g., G major in the key of C). It has a strong pull toward the tonic chord (I).

Subdominant (IV): The fourth chord in a key (e.g., F major in the key of C). It often moves towards the dominant chord in a progression.

Sevenths

A seventh chord adds a seventh note to a triad, creating tension. The most common type is the dominant seventh (e.g., G7 in the key of C), which resolves strongly to the tonic.

Types of Chords

Concord: A consonant, harmonious chord that sounds pleasant and stable (e.g., major and minor chords).

Discord: A dissonant chord that creates tension and sounds unstable (e.g., diminished and augmented chords).

Diatonic and Chromatic

Diatonic: Harmony that uses notes from the key of the piece (e.g., C major in a piece written in C major).

Chromatic: Harmony that uses notes outside of the key, often creating tension or colour (e.g., C, C#, D).

Cadences

Cadences are the harmonic conclusions at the end of a musical phrase, helping to create a sense of resolution or pause.

Perfect Cadence (V-I): A strong, final resolution from the dominant to the tonic, giving a sense of completion.

Imperfect Cadence (I-V or IV-V): An unfinished, open cadence that leaves the listener expecting more.

Interrupted Cadence (V-VI): A surprising cadence where the dominant moves to a minor chord instead of the tonic, often adding tension.

Plagal Cadence (IV-I): A softer, less final cadence, often referred to as the "Amen" cadence because of its use in hymns.

Tierce de Picardie: A major chord used at the end of a piece in a minor key, providing an unexpectedly bright conclusion.

Tonality

Tonal: Music that is based on a key or mode, using a tonic note as the home base (e.g., a piece in C major).

Atonal: Music that lacks a key or tonal centre, avoiding traditional harmonic progressions (e.g., much of Arnold Schoenberg's music).

Modal: Music based on modes (scales different from the major/minor system), often used in medieval and Renaissance music.

Modulation

Modulation is the process of changing from one key to another within a piece of music. This can create contrast and drama:

Common Modulations: From a major key to its dominant (e.g., C major to G major) or relative minor (e.g., C major to A minor).

Drone, Pedal, and Ground Bass

Drone: A continuous note held throughout a piece or section, often found in folk music.

Pedal: A sustained or repeated note (often the tonic or dominant) played under changing harmonies, creating tension.

Ground Bass: A repeating bass line over which the upper parts vary, used often in Baroque music.