Harmonic seventh chord
modern addition (which is formally referred to as a tag) to the song "Happy Birthday to You" When sung by professional singers, the harmony on the word "more" typically takes the form of a harmonic seventh chord.
[5] Wendy Carlos's alpha scale has, "excellent harmonic seventh chords ... using the inversion of 7:4, i.e. 8 / 7 " (a septimal whole tone).
It is suggested that the harmonic seventh on the dominant not be used as a suspension, since this would create a mistuned fourth over the tonic.
22 equal temperament avoids this problem because it tempers out this comma, while still offering a reasonably good approximation of the harmonic seventh chord.
"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.
It's easy: You can't mistake it, for the signs are clear; the overtones will ring in your ears; you'll experience a spinal shiver; bumps will stand out on your arms; you'll rise a trifle in your seat.It is normally voiced with the lowest note (the bass) on a root or a fifth, and its close harmony sound is one of the hallmarks of barbershop music.
Audacity can be used to render pure tone versions of the harmonic seventh with both equal-tempered and just tuning.
