Audio: root (0:08)
root plays two part harmony in the key of C on a Rhodes piano with a chorus effect. The root figure, the score, shows that the root of each chord is as follows:
A root is a note. It serves two purposes:
A root is simple in concept, but slippery in practice, so it is useful to spell out what it is not:
A root might seem like smoke and mirrors but it has a definite role in harmony.
The root is a dual-purpose note. It is used to construct a chord and every chord has a root note. It is used to construct a chord progression and a succession of root notes is a chord progression. The root note integrates the static and dynamic elements of harmony.
The root is probably the most powerful tool for writing harmony. It provides a mechanism for writing individual chords and a mechanism for writing chord progressions. It is only a single note yet it fulfils two distinct roles. Not only that, a succession of root notes in the same part constitutes a melody. No other mechanism is so simple yet so powerful. It is an absolute boon to music writers.
The use of a root also enables us to address an interesting issue in harmony: when is a chord complete? The trite answer happens to be the correct one: when you decide it is complete. Let us unpick what this means.
The terms, complete chord and incomplete chord, are used in harmony. The triad, a chord with three notes, is a complete chord. A chord with two notes is thus incomplete, by definition. Three notes are the minimum for a chord to be considered complete.
Unfortunately, there is a circular definition at work: a chord is deemed complete if it contains three notes because a chord is defined as containing three notes. In principle, any two note chord is an incomplete three note chord, any three note chord is an incomplete four note chord, and so on. No chord will ever be complete unless it contains all the notes available.
Completeness does have one use in writing music, it can act as a placeholder for expanding an existing harmony. root illustrates this approach. In bars 1-4, each bar contains three different notes that form a complete triad. In bars 5-8, each bar contains only two different notes forming an incomplete triad. However, the notation for bars 5-8 identifies the larger chord of which the two notes form a part. In this way, the harmony can be completed at a later stage by adding the missing note and the piece expanded from two part to three part harmony. This demonstrates what an incomplete chord should do: provide a route for harmonic expansion.
A root, sounded or silent, is a mechanism for writing incomplete and complete chords. What a terrific tool to write music with. All hail the mighty root!