Show off your theory chops with my weekly challenge! You’ll find a new question here every Monday. Please comment to post your reply.
This week’s challenge:
In common practice harmony, why does a 3rd-inversion V7 chord resolve to i6, not root-position tonic?
Reply to post your answer, and check back on Friday, December 17th to see if you’re right!
ANSWER for 12/13/21
The V7 chord has two tendency tones: its 3rd (TI) and its 7th (FA). The natural resolution of TI is up to DO, and FA resolves down to MI (or ME if we’re in minor). These resolutions occur regardless of what inversion the V7 chord is in. So in a third inversion V7 chord (V4/2), the chord’s 7th is in the bass, and must resolve down to the 3rd of the tonic chord. Watch these two excerpts from the Breaking Barlines diatonic harmony video for more detail:
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Because the seventh of the chord needs to resolve down stepwise. In the example above that means the G resolving down to an F. That F is the third of the chord which necessitates a i6.
1) I think the 4 to b3 qualifies as a tendency tone even tho its a whole, not half step.
2) Its clearly the best bass line voice leading
3) the 4 to 1 in the bass line may sound plagal, even though it authentic.
one of those must be right. 🙂
Two reasons. 1 the seventh has a tendency to resolve down. 2. In the context of the piece we just had a fairly strong half cadence – really a perfect authentic on the dominant. The base line is now moving step down to the tonic before making an imperfect authentic on the tonic. The base motion is moving downward stepwise from the ‘a’ in the half cadence to tonic where it closes the phrase by doing a IV6 –
I-64 – V7 – I cadence. If the bass had moved directly to the tonic, the four measure movement in the bass to the tonic would have been messed up because the tonic would have been reached too early.
I agree with your analysis it’s also many times used as a passing V6/4 And for voice leading would move to the I6
Lest we forget the tritone? This harmonic tension typically resolves in contrary motion. Thus, the C-sharp moves up to D and the G moves down to F. Essentially, the tritone resolves to the interval of a 6th. Maintaining the common tone A, the chord resolves to a 6-3 inversion.
Absolutely, the tritone created by the 3rd and the 7th of the V7 chord demands resolution in contrary motion, no matter what inversion the chord is in.