Magic Choral Trick #112 Balancing the Dominant 7th Chord
Although the Dominant 7th chord appears in every genre of choral music, it’s Barbershoppers who have it as a staple part of their diet. I’ve never known any other choral musicians to take it so seriously.
The same rules apply here as with the Major chord – Root and Fifth predominant, with the Third just laid in gently. The only addition with the Dominant 7th is the 7th itself – which, like the Third is just lightly breathed into place.
This is usually not difficult to balance in a Barbershop chorus because the 7th is often given to the Tenors, who sing the top part, and who are deliberately very few in number. In a chorus of about 25 singers, the best Tenor balance would be achieved by having 2 Tenors. (though it seems that it’s always prudent to have one more in case one is laid low by illness)
In a regular choir it may take a little more reminding and convincing to get the part singing the 7th to back off a bit.
When the chord is inverted, and the Root is on the top right next to the 7th, the plan is a little different. In Barbershop this is called (for reasons that I really don’t know) a Chinese 7th.
I’m going to give the last word on this to Barbershop Harmony Society judge and coach Ig Jakovac:
“To properly balance a “Chinese seventh”, the root (typically sung by the tenor) needs to be really predominant followed by the fifth – also, I have found that there is almost never enough third in this type of chord.”