Aldwell-Schachter Chapter 20
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All accented 6/4 chords work more or less the same way as the cadential 6/4. The same principle that informs the cadential 6/4 can be used with other roots as well. Here a 鈥淚V 6/4鈥 is functioning as a tonic with a double accented upper neighbor tone.
This progression involves the use of a V6/5, which is approached via 6/6/4, which then resolves to 6/5/3. This is a rather typical progression in minor. It is followed by yet another accented 6/4 on 鈥榠鈥, as above.
This is very nearly a vii6鈥攖he difference is all of one note, and there isn鈥檛 any functional difference. The 鈥淰6/4鈥 here has all the root integrity of the vii6, which is to say, no root integrity at all.
Here a 鈥渧i6/4鈥 acts as a passing tone between ii and ii6; it is really acting much as a I6 might act under similar circumstances.
Passing 鈥淚6/4鈥 between IV6 and ii6/5. As Aldwell-Schachter put it, this is a VERY FREQUENT progression.
Passing 鈥淰I6/4鈥 between ii6/5 and ii7 in minor. Notice how this allows for incredibly smooth voice leading, which makes clear just how contrapuntal all of these progressions really are.
Here is a passing 鈥淚V6/4鈥 which works over a stationary bass, allowing a contrapuntal motion to V6 and hence to vi. It is interesting to note that here the 鈥渓eading tone鈥 of the V6/3 has been doubled, but in this instance it isn鈥檛 really acting as a leading tone (not moving to I) so it isn鈥檛 bothersome. A leading tone that doesn鈥檛 lead isn鈥檛 a leading tone.
This looks almost like anarchy; a 鈥淚6/4鈥 connecting a V7 to a V! The V7 never resolves, it would appear. But actually it does鈥攊n the next measure. The trick here is to realize that we are hearing an expansion of V7 that is working because of the ear鈥檚 ability to recognize contrapuntal motion that doesn鈥檛 have a strong harmonic component.
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Along similar lines, this expanded progression shows elaborated 6/4 chords over a sustained bass. The figure has been written twice鈥攖he first time with a stepwise descending soprano, and the second time using a characteristic voice-exchange technique.
This could really be thought of as a long expanded tonic. The actual figures are given in the analysis, although they seem a little silly under the circumstances.
An interpolated ii6 here expands the cadential 6/4 just a bit. The analysis style used here helps make clear the interpolation, by placing the 鈥榠i6/3鈥 at a different vertical level from the cadential 6/4. Parentheses around the ii6/3 can also have the same effect.
This looks for all the world like an improperly written cadential 6/4, with the 6/4 on a weak beat. But it doesn鈥檛 sound like a cadential 6/4. That is because this is really a passing chord, created by contrapuntal motion. In that aspect it is almost identical to the earlier progression IV6/3-鈥淚6/4鈥-ii6/5.
Just to clarify, here is the same progression as the one above, using IV6/3-鈥淚6/4鈥-ii6/5.
Rather along the same lines as passing 6/4 chords above a stationary bass, here the 6/4 chords have been produced by a voice exchange in the outer voices. You may safely assume this section of the chapter as padding. The section that follows is also padding, so we鈥檙e skipping it.