Root (chord)

In the music theory of harmony, the root is a specific note that names and typifies a given chord.

For instance, the root of a triad such as E Minor is E, independently of the vertical order in which the three notes (E, G and B) are presented.

[3] The first mentions of the relation of inversion between triads appears in Otto Sigfried Harnish's Artis musicae (1608), which describes perfect triads in which the lower note of the fifth is expressed in its own position, and imperfect ones, in which the base (i.e., root) of the chord appears only higher.

[4] Thomas Campion, A New Way of Making Fowre Parts in Conterpoint, London, c. 1618, notes that when chords are in first inversions (sixths), the bass is not "a true base", which is implicitly a third lower.

[5] Full recognition of the relationship between the triad and its inversions is generally credited to Jean-Philippe Rameau and his Traité d’harmonie (1722).

The effect is increased by the fact that the missing fundamental also is the difference tone of the harmonic partials.

[13] The diminished seventh chord affords, "singular facilities for modulation", as it may be notated four ways, to represent four different assumed roots.

The fundamental bass (basse fondamentale) is a concept proposed by Jean-Philippe Rameau, derived from the thoroughbass, to notate what would today be called the progression of chord roots rather than the actual lowest note found in the music, the bassline.

Subsequently, music theory has typically treated chordal roots as the defining feature of harmony.

The root progression which emerges may not coincide with what we think we have written; it may be better or it may be worse; but art does not permit chance.

The total root progression is heard as a substantive element, almost like another melody, and it determines the tonal basis of the music.

[15]Roman numeral analysis may be said to derive from the theory of the fundamental bass, although it does not particularly theorize the succession of roots.

The theory of the fundamental bass properly speaking has been revived in the 20th century by Arnold Schoenberg,[16] Yizhak Sadaï[17] and Nicolas Meeùs.

Root, in red, of a C major chord ( Play ⓘ ). The root is doubled at the octave .
Root notes (blue) and bass notes (red, both=purple) from an 18th-century Chorale Play ⓘ
Root position, first inversion, and second inversion C major chords Play root position C major chord ⓘ , Play first inversion C major chord ⓘ , or Play second inversion C major chord ⓘ . Chord roots (all the same) in red.
Root position, first inversion, and second inversion chords over C bass Play root position C major chord ⓘ , Play first inversion A minor chord ⓘ , or Play second inversion F major chord ⓘ . Chord roots in red.
Determining chord root from inversion Play ⓘ . "Revoicing inverted triads to root position". [ 1 ]
Root position triads from C major scale [ 2 ] Play ⓘ .
Assumed root, Am 7 /B: A minor ninth chord without root and with B in the bass. [ 7 ] Play ⓘ Am 9 /B, Am 7 , then full Am9.
A comparison of the diminished 7th Play ⓘ and dominant 7th [ 11 ] ( ♭ 9) Play ⓘ chords.
Diminished seventh chord's use in modulation : each assumed root, in parentheses, may be used as a dominant , tonic , or supertonic . [ 12 ] Play ninth chords ⓘ Thus C, taken as dominant, would modulate to F.