Chord Functions

Do you guys agree with my thoughts on chord functions?

Chord functions?  Seems that chord function just depends on what tonic was emphasized by the last V-I chord progression then the following chords can be labeled as Tonic, supertonic, mediant, subdominant, dominant, sum-mediant, and leading tone.  If the tonic C was emphasized by a G-C V-I move then if the next chord that came up was A, the A would function as a sub-mediant chord.  In a sense C functions as a the tonic and A as the sub-mediant.  Or it could function differently depending what scale you are thinking of the moment.  C major or A minor or A Dorian.

You're right about C major having different functions in Major and minor keys.

Essentially, the primary function of a chord is to support the melody.  You may find chords that 'clash', or create dissonance, within the context of a progression, but I've never seen one that didn't work with the melody note... although you may have a temporary clash, the melody note will then move to a chord tone (this is called an appogiatura), or you'll find the chord resolves to something that then supports the melody (this is called a harmonic suspension, not to be confused with a suspended chord).

Moving up a level in analysis, chords will either flow smoothly from one to the next, sharing one or more tones (like F-C, sharing the C note), or will create and release tension (like G7-C).  You can group chords into those that are 'stable' and could stay where they are... like all Major chords, all minor chords, 6/9 chords, 6th chords, etc..... and those that are unstable, and need to move somewhere, like dominant chords, augmented, diminished, altered chords, etc.  You won't find a lot of chord progressions that sit on a 7th chord for more than a measure.

A composer will use the tension created by 'unstable' chords to add interest to a piece.  Since interesting pieces will build and release tension repeatedly, it's worthwhile to map out how this is done through a chord progression.  When you're done, look at how the melody line moves against it -- it will likely be making larger moves during the tension building phases, descending runs during the release phases, etc.

Tom

Or it could function differently depending what scale you are thinking of the moment.  C major or A minor or A Dorian.

Tom could you adress this part of Crash's question?

I'm curious how C could function as belonging to those other scales so immediately after establishing C as the tonic chord or right after the G7 to C move.

Or is it that simple?

C is the tonic and so pitch axis kicks in at that point and you can pivot away on the C root ?

Well, I interpreted this as a typo in Crash's post... he refers to A as being in A minor or A dorian, so I assumed it was an Am chord, rather than an A.

The leap from C to A is hard to pull off in context; although you've got the E in common between the two chords, you're moving the root voice in C up a half-step, and the fifth up a whole step.  That's not out of the question (C to A) because of the common voice with E, but it doesn't put you in either Am or A dorian -- which has a minor quality to it because of the A-B-C in the dorian scale.

So... we're probably talking about a change from C to Am, which is very common -- you're moving to the relative minor key.  You then have TWO voices in common with the C major chord, so it's a very smooth change... just move the C voice down a minor third and you're there.

Tom

Noteboat, picked up a book of compositions.  I'm mapping out the chord progressions, but I quickly came upon a road block.  How would I label chord inversions?  Say the piece is in C major and I come up on F-D-A, would I label this as the II chord or the VII chord?  Thanks

Oh! and also how should an augmented or diminished chord be labeled since they are keyless?  Thanks

Guitar notation usually doesn't indicate the inversion... if you have F-D-A, you've got a Dm chord (D-F-A).  Some folks will note the bass with a slash, as in D/F.  That still doesn't tell you the other voices; it's one of the things that's left to the discretion of the guitarist as a rule.

That's not to say there aren't systems for noting specific inversions.  The most widely used (which is still pretty rare outside of theory books) is called figured bass.  In very early keyboard music, a melody line was written out, and roman numerals indicated what the left hand should do at the same time.  Inversions were very important here, and they devised a system to indicate very specific inversions.  A web search on figured bass will probably bring you some decent reading material here -- it's difficult for me to give examples using just text.

Diminished chords aren't keyless -- they naturally occur on the 7th degree of a scale.  In the key of C, the naturally occurring triad will be B-D-F, which is Bº.

Augmented chords will occur in minor keys on the III, assuming you've raised the 7th (in melodic minor ascending, or harmonic minor).  In Am, you get C-E-G# in either harmonic scale -- but not on the natural minor.

Augmented chords don't fit into any key, major or minor, unless at least one scale step is altered... in the minor keys, you're raising the 7th, or the 6th and 7th, so you're using accidentals outside the key signature.

Tom

Alright, I printed some info off the web yesterday and I learned how to label chords using figured bass.  Now how do I use this?  What should I be doing now?  Thanks

I don't see augmented chords much in tab books (for rock and light metal).  Would it be safe to say they are played infrequently?  I know I don't see dim chords much, either.

I'd say in popular music, augmented chords are used less often than augmented chords.  In jazz standards, they're probably about equal in use (in the writing), and diminished are more common in improvising as substitutions.

I'd say in popular music, augmented chords are used less often than augmented chords.

You probably meant:

augmented chords are used less often than diminished chords.

Augmented chords don't occur naturally in the major or natural minor scales.  They occur in the harmonic and melodic minors, but sound rather nasty and are thus often avoided.

I started laughing when you said they "sound nasty."  I may have played one or two in my days and don't remember what they sounded like.  So, my mission tonight is to read a few from my chord book and listen in.

Augmented chords don't occur naturally in the major or natural minor scales.  They occur in the harmonic and melodic minors, but sound rather nasty

:D haha

How are they used?
I know you can play the whole tone scale over them
but how are they used in chord substitution etc.?

Is there any way to make them not sound nasty? ;D

thanks,
Derp

I actually like the way they sound...   ;)

Usually one uses an augmented chord to go to the fourth or sixth of that augmented chord's root. The reasoning behind this is that you've created an additional half-step that makes for a very pleasant voice leading.

So, for instance, instead of C going to F (or F/C if you prefer):

G goes up a whole step to A

E goes up a half step to F

C remains the same

You've got Caug going to F:

G#  goes up a half step to A

E goes up a half step to F

C remains the same

The cool thing about augmented chord is that, like diminished sevenths, the intervals involved (two whole steps between each note) can be divided into 12 (total number of half steps) perfectly. So guess what:

Caug   =   C,     E,     G#

Eaug   =   E,     G#,   C

G#aug =  G#,   C(B#),   E (D##)

Which allows you to use agumented chords for great pivots between keys.

As far as substitutions, in Jazz you will often see an augmented chord (with dominant 7th added) used in place of a regular dominant seventh, particularly on a turn around between verses.

So a progression of Dm, G7, C can become Dm, Gaug7, C (or C6).

Hope this helps.

Peace