Show off your music theory chops with my weekly challenge! You’ll find a new question posted here every Monday, and you can comment to post your reply.
This week’s challenge:
When writing in four voices, what’s the best note of an Italian augmented sixth chord to double?
- A) The Root
- B) The Third
- C) The Sixth
Hint: choose the option that avoids parallel octaves.
CHECK BACK on Friday, 4/9 for the answer!
B) The Third. The Italian sixth is the only augmented sixth chord with only three notes, so in a four-voice texture one of them has to be doubled. If you double either the root or the sixth, you get parallel octaves. The only note in the chord that can resolve either up or down is the third, so this is the best note to double. On the staff below, we have an Ab Italian sixth resolving to the V chord in the key of C minor. The third of the Italian sixth, C, can either resolve up to D or down to B. So the alto and tenor double this third, thereby avoiding parallel octaves.