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This Notice the I, IV, and V chords are the only ones with unambiguous functionality (except B{{dim}} which is covered [[B Diminished|later]]. Ordering those chords by harmonic functions gives us our first and most basic chord progression: I - IV - V - I:
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{{Beginner Lesson Crumbs|16}}
This lesson is intended to give a basic understanding of harmonic function related to a major key, designed to analyze and create chord progressions. Examples are given in the key of C Major.
== PreReqs ==
|Music Theory - Diatonic Chord Progressions#Cadences|Cadences}}
Chords are considered <u>'''diatonic</u> ''' to a particular key if they only contain notes found inside that key. The major scale has 7 distinct notes, giving us 7 possible choices for the roots of diatonic chords. Using the 3rds and 5ths of each root that are also found inside the key gives each chord a particular quality. In a major key, there are 3 major, 3 minor, and 1 diminished diatonic chords.
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|Music Theory - Diatonic Chord Progressions#Cadences|Cadences}}
At the most basic level of abstraction, each diatonic chord has one of three <u>harmonic functions</u>: '''tonic''', '''pre-dominant''', or '''dominant'''. The function of tonic chords is to establish tonality or resolve tension. Thus it is often the first and/or last chord in a song. Dominant functions to create tension that can be relieved by tonic chords. Pre-dominant chords serves to lead away from tonic chords and into dominant chords. Here is a table with all the diatonic chords and their functionfor C Major:
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C F/C G/B C
Those are a bit different, but they all seem to "push" in the same direction, right?
So if all these chords fall into these functions and each one leads into the next one, how do we composecreate unique compositions? ''It may feel like these rules are locking us inside a cage where we can make a substitution here and there but aren't really free to branch out.'' Here are several points to keep in mind:
* We are only using diatonic chords.
* We are immediately moving from one function to the next, rather than hanging around and embellishing the function before moving on.
* We are confined to one key instead of [[Modulation|modulating ]] or [[Chromatic Chords|borrowing from other keys]].
* We haven't entertained the idea that we can ignore the functions described above, or that other contrary functions may exist.
* We are only looking at harmony, without any context of melody or rhythm. Even with all the points above, a seemingly simple progression can undertone a wide range of actual songs. Check out the [http://www.youtube.com/watch?v=5pidokakU4I ''4 chord song'' by '''''Axis of Awesome'''''].
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|Music Theory - Diatonic Chord Progressions#Cadences|Cadences}}
Another way to progress through chords is given to us by the [[Circle of Fifths|circle of fifths]]. We haven't covered that yet, but we will soon. Essentially, it arranges notes in order of fifths, with each note being a perfect fifth higher than the previous note as we traverse the circle clockwise. Here's the notes from C{{flat}} to C{{sharp}} along the circle of fifths.
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Cb - Gb - Db - Ab - Eb - Bb - F - C - G - D - A - E - B - F# - C#
Enharmonically, G{{flat}} and F{{sharp}} are the same pitch(as are C{{b}} and B); so the circle is just repeating at that point, indicated by the range above the notes above.
If we use only diatonic notes for any particular major key, the 7th note does not have a diatonic perfect fifth but a diminished fifth. In C Major, B-F is a diminished fifth instead of a perfect fifth; however, we can still make the circle by using ''diatonic'' 5ths, substituting in the d5 as appropriate. This makes the "circle" smaller:
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F - C - G - D - A - E - B - F - C
We have already learned that the strongest harmonic resolution is from Dominant to Tonic (or V - I). The circle progression makes use of this - we simply traverse the circle counter-clockwisebackwards, so that the root note of the next chord is a 5th below (or inversely a 4th above) the current one. So in the key of C Major, a complete circle progression is:
C - F - B{{dim}} - Em - Am - Dm - G - C
e---------0-----------3------
Every chord leads into the next pretty seamlessly. Notice we basically have 2 passes through the tonic - subdominant - dominant - tonic paradigm of harmonic function. I - IV - iii - vi and vi - ii - V - I.
The circle progression gives us a basic roadmap of how to get from any chord to any other chord in the same key. Knowing harmonic function allows us to take "shortcuts" and jump some intermediate chords. For example, we know the harmonic function of IV is pre-dominant, so we can jump from IV to any dominant function chord. Let's choose V. That leaves us with I - IV ... - V - I. We're back to our basic I - IV - V - I example!
|Music Theory - Diatonic Chord Progressions#Cadences|Cadences}}
Let's make up a song real quick. We will use the key of C Major (do we have a choice yet?) and want to start on the tonic. Let's add some rhythmic variety. We'll stay on the C Major major chord for a full measure, which will help really establish the key of C Major. Then let's repeat the part of the circle progression again from iii to ii. We know that ii is a predominant function and iii can have a dominant (as well as tonic) function, so let's dwell on the ii for an extra beat, then go back to iii. From iii we circle progress again, but instead of stopping at ii, this time we'll keep going to V.
C Em Am Dm Em Am Dm G C
Here, we are simply ascending the C Major scale, with each note used as the root of the next chord in the sequence: C Dm Em F G Am. ii has a predominant function, so it's no so bad that it leads into iii, but this implies the iii has a dominant function. The next chord is IV, the main pre-dominant chord. iii - IV might work if the iii has a tonic function, but in this case it doesn't; and the transition will sound awkward. IV - V is common and worry-free progression, but the following V - vi hurts the dominant functionality of the V. Even though vi can have tonic functionality, it is much less strong than the V - I, dominant - tonic resolution. Then we have vi - I. The vi likely serves a tonic functionality here, coming off the preceding V. This makes the vi - I progression weak and uneventful, probably the opposite of what is desired leading into the last chord of the piece.
Again, is this example 100% terrible? Not really. Since we are using only chords diatonic to C Major, the tonality is still grounded and evident, which is enhanced by starting and ending on the C major chord. We have mucked up harmonic function, but we haven't destroyed tonality. A ''truly, absolutely terrible'' example, would basically feature ''random'' chords from various keys, seemingly having no tonality or direction.
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|Music Theory - Diatonic Chord Progressions#Interrupted/Deceptive Cadence|Deceptive}}
An <u>'''Authentic Cadence</u> ''' is a dominant-tonic progression. The [[7th Chords|dominant 7th (covered later in a later lesson)]] can be used in place of the dominant triad. A <u>'''''perfect'' authentic cadence</u> ''' must use the V or V{{7}} chord as the dominant, have both chords in root position, and voice the tonic note in the tonic chord in the highest voice. An <u>'''''imperfect'' authentic cadence</u> ''' is similar, but breaks one or more of the above conditions. It may substitute the vii{{dim}} chord for the V.
=== Half Cadence ===
|Music Theory - Diatonic Chord Progressions#Interrupted/Deceptive Cadence|Deceptive}}
A <u>'''Half Cadence</u> ''' is a progression that moves from basically any chord to the V chord, leaving a sense of unresolved tension. The cadence is still designed to indicate the end of a phrase or musical idea, but it begs for continuation, either through a repetition or another idea/section.
=== Plagal Cadence ===
|Music Theory - Diatonic Chord Progressions#Interrupted/Deceptive Cadence|Deceptive}}
A <u>'''Plagal Cadence</u> ''' is a IV - I progression, also called the "Amen Cadence" because of its frequent use in church hymns. Because there is no leading tone to tonic movement, the cadence does not imply tonality. For instance a I-IV-I progression could also be interpreted as a V-I-V progression. In this way, it is a weak resolution, but a resolution to tonic, nonetheless.
=== Interrupted/Deceptive Cadence ===
|Music Theory - Diatonic Chord Progressions#Interrupted/Deceptive Cadence|Deceptive}}
An <u>'''interrupted or deceptive cadence</u> ''' is a V-vi or V-VI progression, commonly using V{{7}}. This creates a weak or suspended feeling, similar to the half cadence.
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