Melody delivers soul to music, rhythm expresses harmony and dynamics make the tempo.
The word harmony comes from the Greek word 'ἁρμονία' or harmonia, meaning 'joint, fit together'. Harmony in music refers to how chords are constructed and the system by which one chord follows another chord in time. Harmony functions as an accompaniment to melody. A basic three-tone chord or triad consists of three notes: the root, the third above the root, and the fifth above the root. In Western diatonic music the harmonies are based on building triads from a major scale. For example in a C major scale C D E F G A B C, a C chord is created by three notes: C, E, and G. The note "C" is the root, with the notes "E" and "G" providing harmony. Chords are also notated by the scale degree of their root note. The degrees are identified by Roman numerals. For example, the first scale degree of the C major scale is the note C, a triad chord built on top of the note C would be called the chord I or scale degree I. The seventh and last scale degree of the C major scale is the note B, a triad chord built on top of the note B would be called the chord VII or scale degree VII. When starting and ending on any note within a scale, we create different "modes" of the same scale. The tonic or root note in the C major scale is C. If we establish a new tonic on one of the notes other than C, for instance D, we have a mode. The new mode on D has these notes: D, E, F, G, A, B, C, D. This is the Dorian mode. New modes may be created the same way on the other notes of the major scale. The modes of the C major scale are: Ionian/major Scale: C, D, E, F, G, A, B, C. Dorian: D, E, F, G, A, B, C, D. Phrygian: E, F, G, A, B, C, D, E. Lydian: F, G, A, B, C, D, E, F. Mixolydian: G, A, B, C, D, E, F, G. Aeolian/Natural minor scale: A, B, C, D, E, F, G, A. Locrian: B, C, D, E, F, G, A, B.
The Harmonic Wheel is a new representation of Sounds, where the Consonance Relationships among them are clearly shown. It is, therefore, a powerful tool for the comprehension of Music Theory and Harmony. It consists of two rotating discs, one being card and the other plastic.
Among other features, it shows a complete and panoramic view of the relationships among all keys. While the cycle of fifths shows the keys on a line (one dimension), the Harmonic Wheel shows them on a surface (two dimensions). So, besides the cycle of fifths, the relative and parallel keys are also visible. Thus, a real MAP OF THE KEYS is achieved. Both the BÉLA BARTÓK’S AXIS SYSTEM and the COLTRANE CHANGES IN JAZZ perfectly fit in this representation.