Triads in 2nd Inversion

 

Logic would tell us that we would triads in the second inversion the same way we use the first; arpeggiations and substitutes for the root. While sometimes a second inversion is used in an arpeggiations, they will not be used to substitute for the root. This stems from the fact that classical composers often found the interval of a P4 from the bass in a chord to be a dissonant interval, and that mind set has carried over into the way Western Classical music is composed today. This applies to major, minor, diminished (+4 from root), and augmented (dim 4 above root). Since this chord sounds more unstable than the root position and first inversion triad, there are very specific uses of the 64 chord. For our purposes, a deviation from these reasons will be considered wrong (as it will on the AP test).

 

Bass Arpeggiation and the Melodic Bass

As we saw on the last chapter, through the use of bass arpeggiation, we will see both first and second position triads (with the 3rd and the 5th in the bass). Our goal as analyzers, and later as composers, will be to recognize when a second inversion is really just an extension of the tonic in root position arpeggiating.  A similar situation can arise by having a melodic line in the bass. While we might play the 5th of a triad in the bass in this example, it will still not be definitive enough to suggest that we are actually outlining a second inversion chord, but will instead just seem like a natural exploration in the root position. Take a look at examples 9-2 and 9-3 to see an example of both things.

 

Cadential Six-Four

The first, and most common, example of the 64 chord given in the book is the cadential six-four (which we first learned of in the last chapter). By looking at Example 9-4, we can see that the I64 chord is serving the purpose of prolonging and enhancing the cadence by preceding the V chord. This is an extension of the dominant function in this progression, and makes the cadence a little more interesting by delaying the dominant that the listener expects (it has a “things falling into place feeling” to me).

The important thing to note is that the cadential six-four chord does not represent a statement of the tonic, but instead is a continuation of the dominant. Take note that the book has bracketed off both the I64 and the V chord with a designation of V in Example 9-4. When we use the cadential six-four, we will use this technique to let the reader know that the I64 is intended to serve with the five in the dominant function. Take note how smoothly voices move in and out of the I64 in both example 9-4 and 9-5. Scale degrees 1and 3 usually resolve to 7 and 2 respectively. Also take note that composers often attempt to put a cadential six-four on a week beat, and then move to the V chord on a strong beat. The easiest example to feel the effect of delaying the dominant is often heard in a large orchestra piece during a cadenza section. The orchestra will often end a cadential six-four chord, and the soloist will then play their cadenza. This serves to leave the listener not only listening to the soloist demonstrating skill on the cadenza, but expecting the orchestra to return at any time to play the dominant to tonic, and thus complete the progression.

 

Passing Six-Four

The second type of acceptable use of the six-four chord is a passing six-four. This occurs when composers when a six-four is implied by a three note scalar passage. This can occur either ascending or descending, and will occur on the weak beat like the cadential six-four.  In Example 9-8, the bass goes from the I in root position, up the scale to the second scale degree, and ends the measure on the scale degree three, which is the bass note of a I6 (first inversion) chord. The book notes in parenthesis that the chord implied by the second scale degree is the V chord in second inversion. Take note that they put this chord in parenthesis to note that it is passing and does not serve as harmonic movement. Think of it like flight to San Francisco from Nashville that makes a stop in Denver to get there. Although you touch down and switch flights in Denver, you wouldn’t really say you went on vacation there: you just passed through en route to your real location.

One should also take note that in example 9-8 there is a voice exchange between bass and soprano (a-b-c# in the bass and c#-b-a in the soprano), and movement of a parallel sixth in the example 9-8b (with voice exchange between bass and tenor). Both of these are common in the case of the passing six-four.

 

Pedal Six-Four

The last example of an acceptable six-four chord is the pedal six-four.  In this type of movement, a static root position triad is augmented to bring some movement. The bass will hold steady on the tonic note, and the third and fifth scale notes will be raised up a step and then brought back down, resulting in a 64 chord. We will notate this with a parenthesis, like the passing six-four. The two most common uses of the pedal six-four are the I (IV64) I movement, and the V (I64) V movement, and the 64 chord will once again fall on a weak beat.

 

Part Writing for Second Inversion Triads

When writing a second inversion chord for four parts, the bass (the 5th of the chord) should be doubled, with the other voices moving as smooth as possible.  In three voice writing, it is best to have all three voices present, but if the root or 3rd is missing, double the 5th.