18a Discussion - Augmented sixth chords

AAAAAAAUUUUUGGGGHHHmented Sixth Chords

“What are they?”

• They are a collection tendency tones
• Their main purpose is to lead into a V chord
• They always contain an augmented sixth interval

“How are they made?”

• They all contain Do of their home key
• They all contain Le and Fi
• When spelled out, Le goes on the bottomm and Fi goes on the top. This is how you get an augmented sixth interval within the chord.

Italian:

• It⁺⁶
• Solfege: Le, Do, Fi
• Scale degrees: b6, 1, #4
• Italian is the “base model” version, which includes only the three necessary chord tones to make an augmented sixth chord.
• Le always resolves down to So, and Fi always resolves up to So. Do is the only chord tone that gets doubled, becuase it can resolve in different ways.

French:

• Fr⁺⁶
• Solfege: Le, Do, Re, Fi
• Scale degrees: b6, 1, 2, #4
• French adds “Re”, which can carry through to the V chord, not needing to move.
• Le always resolves down to So, and Fi always resolves up to So. Do will reslve to Ti if going to a V chord, and Re will remain as Re if going to a V chord.
• If it is used to go to a cadential 6/4 in minor, Re will go to Me.

German:

• Ger⁺⁶
• Solfege: Le, Do, Me, Fi
• Scale degrees: b6, 1, b3, #4
• German adds “Me”
• Le always resolves down to So, and Fi always resolves up to So. Me creates a voice leading issue because it resolves in parallel perfect fifths with Le.

Additional Notes:

• The leadsheet notation for these chords are the same as the roman numerals.
• The augmented sixth chord is almost always predominant function, because they almost always resolve to V, or I6/4.
• There are no inversions of these chords, becuase they are not triads.

Steps for Building an Augmented sixth chord in any key:

1. Write in “Do”.
2. Figure out what is “So”.
3. Underneath Do, write in the note that is a half-step above So.
4. Above Do, write in the note that is a half-step below So.

Class discussion 2022

Augmented sixth chords resolving to a non-dominant harmony

• By writing some notes enharmonically, we can basically sub in one dominant chord for another. In the example we did in class (in C), the respelled Ger+6 translated to a Db7, which still moved nicely over to V7.
  • Process: writing out the full chord (Db F Ab B) and respelling the B as a Cb. Cb wants to resolve down to the B in the next chord, and the F carries through to be the seventh.
• If you keep the chord as written, we have our normal +6 chord function: the actual +6 resolves outward to the root of the next chord. So our original +6 chord from the example resolves to a C major chord.
  • Labeling: instead of using our “in the key of” secondary dominant labeling, the slash indicates “going to” and you write the scale degree below the slash. The Ger+6 in this example would be written as Ger+6/^1 (remember the caret should be written above the number)
  • In this instance, Ger+6/^1 actually has dominant function, rather than predominant. It subs in for V7 and proceeds straight to I. Think of respelling the chord as a Db7! Ger+6s can have dominant function…but only sometimes