Train Wreck Twist in Four-Part Harmony
Four-part a cappella can be a delight to perform, especially in the very small choir. On the other hand, it is painful to a director to conduct a train wreck. This one happened when a strong-voiced, weak-reading soprano made one of her intermittent appearances with the choir. The choir had started learning this piece of music without her.
Very often the two upper voices move in duet-at-thirds. (We’ll say “soprano” and “alto” here; the men’s choir uses different terms.) Much less often, the soprano and tenor parts duet similarly, but with a subtle twist. The duetting twist is easy to understand and be forewarned of.
In the upper-voice duet the soprano line keeps station at thirds above the alto line. The soprano-tenor duet typically puts the tenor at sixths below the soprano. Duetting-at-sixths plays in the ear’s mind similarly because the inversion of the tenor line –its octave-above image– imparts the familiar duet-at-thirds feel.
The twist consists in that the soprano line in duet-at-sixths takes the lower role in the duet-at-thirds view.
Now, the lower role in anything does not accord with how the universe is ordered for a special kind of person.
On the memorable occasion I’m reporting, the piece began in a tenor-soprano duet-at-sixths. I gave pitches and we began. Instinctively our diva-in-resonance took her noble station a third above the tenor’s octave-inversion line, thus hijacking the key upwards. No-one knew how to continue with the competing harmonic structures, so I pulled the emergency brake handle.