dominant chords in Barbershop?

>>I'm not familiar with Forte, or with a good definition of "functional
>>harmony". But I know what a dominant chord is. Barbershop music contains
>>plenty of them, often tuned 4:5:6:7. It also contains tetrads which are
>>not dominant chords, and are tuned 4:5:6:7, and in fact this latter type
>>of chord is at least as plentiful as the former type in the typical
>>Barbershop performance.
>
>Really? They're not secondary dominants or deceptive dominants? Can you
>give an example?

Barbershop songs modulate primarily by fifths, just as the songs of most
genres. So if you wanted, you could describe most of the 7th chords as
being dominants of their successors. But the successor is also a "dominant"
7th, and so on. Such an analysis wouldn't add much insight to the music,
though. And there are many progressions which would not succumb to even
this perverse treatment; 4:5:6:7 tetrads are often connected by tritones,
thirds, and half-steps.

Here's a phrase from "Down Our Way", the first Barbershop tune I ever sang
in a quartet...

F7 - Cm7 - E7 - F7
"How do you do?"

The E7 is a typical half-step "passing chord". Okay, here's a tag called
"Our Last Goodbye"...

Bb7 - G7 - G7 - F#7 - C7 - Dm7 - BbM
"Will this be our last good bye?"

Here we have a modulation by a minor third, then a local dominant-tonic
modulation is split into a half-step and a tritone. Then we return
symmetrically -- the Dm7 subs for the G7, and back to the tonic (by a
third).

Here's a classic tag called "Rainbows in the Sky"...

BbM -- Bb7 - F#7 - C7 - C79 - Gm6 - Am - C7 - F7 - Dm - F7 - Eb6+9 - BbM
"There will be rai - ain - bows in the Sky---------y some day."

-Carl

Carl, one could give a meaningful functional analysis for all your examples.
This is not the list for that -- there might be a music theory list
somewhere for you. In the meantime, take a look at Forte and Mathieu (you'll
absolutely _love_ the latter). Mathieu shows how, in the right contexts, a
G7 chord can resolve _functionally_ to 27 different major or minor triads,
including all 24 12-tET equivalence classes.