Musical Chord Types and intervals
Exploring the Chord types and intervals
Chord, in music, a set of sounds that sound simultaneously. Chords are classified by the interval generated between their notes and are counted from bottom to top. The most common type of chord is the triad, which is constructed with two consecutive thirds or a third and a fifth. If the interval of the lower third is major and the upper third is minor, it is a major chord or triad (as in C major: C, E and G).
If the intervals are in the order minor third-major third, then it is a minor chord (as in C minor: C, E flat and G, or A minor: A, C and E). Less common are diminished chords (two consecutive minor thirds, as in B, D and F, and augmented chords (two major thirds, as in C, E and G sharp). Perfect chord is a three-sound chord made up of one note root, a third (major or minor), and a perfect fifth. Chords can also be described as a combination of third intervals (such as between C and E) and fifth intervals (such as between C and G), both counting from the note of the bass (in this case, C).
If more thirds are grouped on the triad, the result is seventh, ninth, eleventh, and other chords. The notes of a chord can be doubled, arbitrarily mixed, or spread out in an arpeggio. The top note of the chord determines its position, which can be 8th, 5th or 3rd. The interval generated between the lower and upper notes of a seventh chord is a seventh, hence the name of the chord. The most common seventh chord is called the dominant seventh chord and consists of a major triad to which a minor third is added (such as G, B, D, and F).
It also receives that name because it is the seventh chord that is built on the fifth note of the scale of a certain key, a note called dominant. Seventh chords can also be built on other combinations of major and minor third intervals. One such combination is the diminished seventh chord (a diminished triad plus a minor third, that is, three consecutive minor thirds, as in G, B flat, D flat, and F flat). Jazz musicians often use seventh chords such as G, B, D, and F sharp (a major triad plus a major third).
A chord can be in the fundamental state when the fundamental sound is the lowest note of the chord, and inverted, when the low sound goes to the high note or vice versa. Chords have a very powerful auditory identity, which they even preserve if their notes are arranged in an inverted order. For this reason, both E, G and C (called first inversion), and G, C and E (second inversion) are recognizable by ear as versions of the same C major chord, which in its normal or fundamental position is composed of do, mi and sol.
Other intervals (seconds and fourths, for example) can also be used to construct chords. A chord is an augmented fifth when the 5th of the chord is chromatically altered by a high semitone and a diminished fifth when the 5th of the chord is chromatically altered by a low semitone. Tonal chords are produced when the triad is built on the tonal degrees of the scale (I-IV-V) and modals are built on the modal degrees of the scale (III-VI-VII). Composers such as the Russian Aleksander Skriabin, the German Paul Hindemith or the Hungarian Béla Bartók have explored harmonies based on fourths. The American composers Henry Cowell and Charles Ives have constructed chords from consecutive seconds, forming tonal clusters.
