The harmonic seventh chord is a

major triad In music theory, a major chord is a chord that has a root, a major third, and a perfect fifth. When a chord comprises only these three notes, it is called a major triad. For example, the major triad built on C, called a C major triad, has pitch ...

plus the

harmonic seventh The harmonic seventh interval, also known as the septimal minor seventh, or subminor seventh, is one with an exact 7:4 ratio (about 969 cents). This is somewhat narrower than and is, "particularly sweet", "sweeter in quality" than an "ordinar ...

interval (ratio of 7:4, about 968.826 centsBosanquet, Robert Holford Macdowall (1876). ''An elementary treatise on musical intervals and temperament'', pp. 41-42. Diapason Press; Houten, The Netherlands. .). This interval is somewhat narrower (about 48.77 cents flatter, a septimal quarter tone) and is "sweeter in quality" than an "ordinary""On Certain Novel Aspects of Harmony", p.119. Eustace J. Breakspeare. ''Proceedings of the Musical Association'', 13th Sess., (1886–1887), pp. 113–131. Published by: Oxford University Press on behalf of the Royal Musical Association.

minor seventh In music theory, a minor seventh is one of two musical intervals that span seven staff positions. It is ''minor'' because it is the smaller of the two sevenths, spanning ten semitones. The major seventh spans eleven. For example, the interval fr ...

, which has a just intonation ratio of 9:5 (1017.596 cents), or an equal-temperament ratio of 1000 cents (2:1).

Uses

Since

barbershop music Barbershop vocal harmony, as codified during the barbershop revival era (1930s–present), is a style of a cappella close harmony, or unaccompanied vocal music, characterized by consonant four-part chords for every melody note in a primari ...

tends to be sung in just intonation, the barbershop seventh chord may be accurately termed a harmonic seventh chord. As guitars, pianos, and other equal-temperament instruments cannot play this chord, it is frequently approximated by a dominant seventh chord. A frequently encountered example of the harmonic seventh chord is the last word of the "...and many more!" modern addition (which is formally referred to as a tag) to the song "

Happy Birthday to You "Happy Birthday to You", also known as "Happy Birthday", is a song traditionally sung to celebrate a person's birthday. According to the 1998 ''Guinness World Records'', it is the most recognised song in the English language, followed by " Fo ...

" When sung by professional singers, the harmony on the word "more" typically takes the form of a harmonic seventh chord.Mathieu, W.A. ''Harmonic Experience''. Inner Traditions International; Rochester, Vermont; 1997. , pg. 126 The use of dominant seventh chords in blues may be an approximation of an older practice of using harmonic seventh chords. Wendy Carlos's

alpha scale The α (alpha) scale is a non-octave-repeating musical scale invented by Wendy Carlos and first used on her album ''Beauty in the Beast'' (1986). It is derived from approximating just intervals using multiples of a single interval, but without r ...

has, "excellent harmonic seventh chords...using the inversion of 7:4, i.e., 8/7." . It is suggested that the harmonic seventh on the dominant not be used as a

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, since this would create a mistuned fourth over the tonic. The harmonic seventh of G, F, is lower than the perfect fourth over C, F, by Archytas' comma (27.25 cents).

22 equal temperament In music, 22 equal temperament, called 22-TET, 22-equal division of the octave, EDO, or 22-ET, is the musical temperament, tempered scale derived by dividing the octave into 22 equal steps (equal frequency ratios). Each step represents a frequency ...

avoids this problem because it tempers out this comma, while still offering a reasonably good approximation of the harmonic seventh chord.

Barbershop seventh

The barbershop seventh is the name commonly given by practitioners of

to the seventh of and the major-minor seventh or dominant

seventh chord A seventh chord is a chord consisting of a triad plus a note forming an interval of a seventh above the chord's root. When not otherwise specified, a "seventh chord" usually means a dominant seventh chord: a major triad together with a mi ...

, when it is used in a barbershop arrangement or performance. "Society arrangers believe that a song should contain anywhere from 35 to 60 percent dominant seventh chords to sound 'barbershop'—and when they do, barbershoppers speak of being in 'seventh heaven.'" Barbershop music features both major-minor seventh chords with dominant function (resolving down a perfect fifth), often in chains ( secondary dominants), and nondominant major-minor seventh chords.McNeil, W. K. (2005). ''Encyclopedia Of American Gospel Music'', p.26. . Beginning in the 1940s, barbershop revival singers "have self-consciously tuned their dominant seventh and tonic chord in just intonation to maximize the overlap of common tones, resulting in a ringing sound rich in harmonics" called 'extended sound', 'expanded sound', 'fortified sound', "the voice of the angels".Averill (2003), p.164. The first positive mention of such practice appears to be Reagan, 'Molly' (1944). "Mechanics of Barbershop Harmony", ''Harmonizer''. The example of a dominant chord tuned to 100, 125, 150, and 175 Hz, or the 4th, 5th, 6th, and 7th harmonics of a 25 Hz fundamental is given, making the seventh of the chord a "harmonic seventh". It is normally voiced with the lowest note (the bass) on a root or a fifth, and its

close harmony A chord is in close harmony (also called close position or close structure) if its notes are arranged within a narrow range, usually with no more than an octave between the top and bottom notes. In contrast, a chord is in open harmony (also c ...

sound is one of the hallmarks of barbershop music. When tuned in just intonation (as in barbershop singing), this chord is called a harmonic seventh chord.

Comparison with equal temperament

Audacity can be used to render

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versions of the harmonic seventh with both equal-tempered and just tuning. These signals can also be graphed in order to illustrate the more complex pattern associated with the equal tempered scale. Both chords are based on a pitch of 400 Hz, with the just pitches at 500, 600, and 700 Hz. The figure also shows the discrepancy between the just scale in comparison to the equal-tempered scale (in cents). For example, the just tone at 500 Hz is

flatter A flatter is a coloring specialist within the comic book industry that prepares the inked or sketched comic book page for the colorist with digital art software such as Adobe Photoshop. The specialist does so by selecting the objects on the pa ...

than 503.2 Hz by 13.69 cents. Also, the 600 Hz tone is

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by 1.955 cents, and the 700 Hz tone is flat by 31.17 cents.

References

External links

Play that barbershop chord
(YouTube video) {{DEFAULTSORT:Harmonic Seventh Chord Barbershop music Seventh chords