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 cent (music), cents). This is about 32 cents narrower, with a more stable and consonant sound, than a ...

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 ...

, which has a

just intonation In music, just intonation or pure intonation is a musical tuning, tuning system in which the space between notes' frequency, frequencies (called interval (music), intervals) is a natural number, whole number ratio, ratio. Intervals spaced in thi ...

ratio of 9:5 (1017.596 cents), or an equal-temperament ratio of 1000 cents (2:1).

Uses

Since

barbershop music Barbershop vocal harmony is a style of a cappella close harmony, or unaccompanied vocal music, characterized by consonance and dissonance, consonant four-part chord (music), chords for every melody note in a primarily homorhythmic texture. Eac ...

tends to be sung in

, 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 Domination or dominant may refer to: Society * World domination, structure where one dominant power governs the planet * Colonialism in which one group (usually a nation) invades another region for material gain or to eliminate competition * Ch ...

. 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", or simply "Happy Birthday", is a song traditionally sung to celebrate a person's birthday. According to the 1998 ''Guinness World Records'', it is the most recognized song in the English language, followed by "For He' ...

" When sung by professional singers, the harmony on the word "more" typically takes the form of a harmonic seventh chord. 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 (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 re ...

has, "excellent harmonic seventh chords ... using the inversion of 7:4, i.e. " (a

septimal whole tone In music, the septimal whole tone, septimal major second, supermajor second, or septimal supermajor second is the musical interval exactly or approximately equal to an 8/7 ratio of frequencies.Andrew Horner, Lydia Ayres (2002). ''Cooking with ...

). . It is suggested that the harmonic seventh on the dominant not be used as a

suspension Suspension or suspended may refer to: Science and engineering * Car suspension * Cell suspension or suspension culture, in biology * Guarded suspension, a software design pattern in concurrent programming suspending a method call and the calling ...

, 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- EDO, or 22-ET, is the tempered scale derived by dividing the octave into 22 equal steps (equal frequency ratios). Each step represents a frequency ratio of , or 54.55 cents (). When composing wi ...

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 (music), chord consisting of a triad (music), triad plus a note forming an interval (music), interval of a Interval (music), seventh above the chord's root (chord), root. When not otherwise specified, a "seventh chord" ...

, when it is used in a barbershop arrangement or performance. "Society arrangers believe that a song should contain anywhere from 35–60 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 dominant A secondary chord is an analytical label for a specific harmonic device that is prevalent in the tonal idiom of Western music beginning in the common practice period: the use of diatonic functions for tonicization. Secondary chords are a ...

s), and nondominant major-minor seventh chords. Beginning in the 1940s, barbershop revival singers "have self-consciously tuned their dominant seventh and tonic chord in

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". The first positive mention of such practice appears to be by . 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 ca ...

sound is one of the hallmarks of barbershop music. When tuned in

(as in barbershop singing), this chord is called a ''harmonic seventh chord''.

Comparison with equal temperament

Audacity can be used to render

pure tone In psychoacoustics, a pure tone is a sound with a sinusoidal waveform; that is, a sine wave of constant frequency, phase-shift, and amplitude. By extension, in signal processing a single-frequency tone or pure tone is a purely sinusoidal signal ...

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