Chord Function vs. Chord Type

Many musicians will say the purpose of music is to stir human emotion. Others might say it is to take the listener on a journey. These may sound like the lofty utterances of a pinhead music teacher but it is true. Every genre of music does this – Rap, Country, Classical, Jazz, Pop. Whenever you turn on your mp3 player, you do so because you want to experience a mood other than the one you have without it. You are voluntarily allowing yourself to be moved from one feeling to another. This change is movement – a movement that music is very good at creating and harmony is one of the elements of music that creates this movement.

Harmony is embodied in chords through the combining of different notes. When you understand what types of chords there are and how they function, you will understand how to write music that stirs emotions.

There is a pattern of experience that is uniquely human. It is what all drama and storytelling is based on. It is known as the “dramatic arc” or the “hero’s journey.” Everything from “Star Wars” to “Othello” is based on it. In its simplest form there is a period of stability that soon becomes disrupted. This disruption leads to uncertainty. In the end, a heightened moment of tension occurs and an event happens that saves the day and returns everything to stability.

This hero’s journey exists in every chord progression of every piece of music. There are chords that establish a harmonic home base. They create a feeling of stability and familiarity. Your brain actually understands this even if you’ve never had a music lesson in your life. When you hear these chords, your brain goes, “I got this. Everything’s OK.”

There are other chords that a composer will introduce that challenge the status quo. They introduce something new into the mix that catches the attention of the listener. Your brain goes, “Hey, wait. That’s different.” The change is a cue to the nervous system to take notice. It’s a thing that’s hardwired into us. Change gets our attention. This is an evolutionary trait that we inherited from our ancestors whose lives depended on how well they could detect movement in the bushes. Noticing change is so important to house flies that they only see thing that move because if it doesn’t move, it’s not a threat.

Harmonic movement mirrors emotional movement. The arrangement of chords of a song work to move the listener to a different emotional state.

Finally, the thing that really gets us going are the real threats to our existence. The sound of a dog barking will send a cat racing from the backyard through the cat door in an instant. This sound creates a tension in the cat that is relieved by her finding shelter. Instinct drives us to find ease and stability whenever we encounter tension and that is exactly what some chords create in us when we hear them. This feeling of finding stability is so great that we often let ourselves experience the tension just so we can experience the release. Think bungie jumping, fast driving, and sex.

 This cycle of stability, change, tension, and stability can be created by scale chords. Each chord within a scales has a roll to play in giving a song a feeling of movement. In fact, each note of a scale produces a chord with a different functional name. For example, chords based on the first note of the Major scale are Tonic. Chords based on the second note of the scale are Dorian. Third note – Mediant, etc. (see diagram below).

Chords can be constructed based on each note of a scale.

The diagram above shows chords of the C Major scale. Because all of the chords are based on the C Major scale, they are said to be diatonic to the key of C Major. The term “diatonic” means that the chords belongs to the key. The term “key” is another way to refer to the scale as a whole. The key of C Major is made up of notes of the C Major scale.

Most of these chords I am showing are triad chords (chords with three notes). I could have added more notes to these chords and their functional names would not change. For instance, the fifth note of the Major scale produces a chord with the functional name known as dominant. It would be a dominant chord still if it was made up of only three notes (G,B,D). The fourth note added here changes the type of chord this is, not its function. I’ll explain this in a little while.

The functional names listed on the right side of the diagram above also have a Roman numeral next to them. These symbols are often used to indicate a chord’s harmonic function. If fact, they are more commonly referred to by their Roman numeral. You will hear musicians talk about the one chord (I), or the five chord (V). Referring to chords this ways allows you to talk about the chords of a song without having to spell out its notes.

Now back to stability, change, and tension. Even though each scale has seven functional categories in which to group chords, those functions are almost always reduced to three groups, tonic, sub-dominant, and dominant. These chords are grouped according to how much they contribute to a key’s stability, change, and tension.

Chords are arranged into functional groups based on their ability to move the harmony of a song.

Most chord progressions are the result of choosing a chord or two from one functional group then switching to one or two of another. Musical phrases are ended by moving from tension producing chords (dominant) to chords with a feeling of stability chords (tonic).

Chord progressions choose chords from different functional groups to create harmonic and emotional movement.

In both of these chord progressions above we the harmony moving from the tonic (stability), to the sub-dominant (change), then to the dominant (tension), and returning to the tonic. All chord progressions do this to some degree.

A chord’s function is a relative thing. The C Major scale gives rise to these triads: Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdim. The G Major scale produces these chord: Gmaj, Amin, Bmin, Cmaj, Dmaj, Emin, F#dim. Though four of the same chords (Cmaj, Emin, Amin, Gmaj) appear in each scale, their functions are different. C Major is the tonic chord in the key of C Major. In this key it creates a feeling of stability. However, in the key of G Major the C Major chord is a sub-dominant chord which creates a feeling of change. Same chord, different function and feeling. The chords work differently in these keys because of the other chords that are around them.

The pattern for constructing chords from scales is the same for all scales. Chord functions stay the same relative to the first note of the scale even though the notes are different.

Earlier I said that chords could be formed using each note of the scale as a root note of the chord. Now I will explain how chords are actually formed. This process of creating chords that belong to a scale is called harmonization. To harmonize a scale into its various chords you take each note of that scale and choose note by counting up the scale. Basically, you make chords by picking every other note of the scale starting from your root note. That means a triad chord of the key of C Major that starts on F will skip G, include A, skip B, include C. You can add more notes to this chord by way of the same process. That is, skip D, include E.

Chords can be constructed by adding notes that are a minor and major third apart.

This process creates chords whose notes are separated by the interval of a major or minor third*. How these intervals are arranged in the chord determines what type of chord it is. This formula for chord creation in the key of C Major produces the chords below.
In the diagram above you will notice that the spacing between the notes differs but in a regular way. Some notes are separated by two whole steps (four semi-tones). Some notes are separated by one-and-half steps (three semi-tones). These intervals are what create the different types of chords.

Chord type refers to a chords construction, not necessarily its function. Chord types can be group into these categories: major, minor, diminished, dominant, augmented, suspended. (Augmented and suspended chords are special cases and will not be dealt with here).

A chord’s type should not be confused with its function. A chord’s function has to do with it’s position in the scale. Like a football team each chord has a position to play and like football, some of those players  play different positions when they change teams. A chord’s type can be understood apart from its function or what scale it might belong to. In fact, except for dominant chord types you really cannot be sure of a chord’s function without knowing what key it occurs in.

Regarding the term “dominant,” some confusion occurs around this chord that is based on the fifth note of a scale. In the key of C this note is G. If we make a triad based on this note, we get a G major chord. Since it based on the fifth note of the scale, it is often called a dominant chord. While this is true, it is more accurate to call it a major chord functioning as a dominant. The confusion arises because the word “dominant” can be applied to function as well as type of chord.  A basic dominant chord type is made up of four notes with stacked intervals of major, minor, and minor. The dominant chord type will usually have a 7, 9, 11, or 13 after it, for instance, G7, C9, D7#9, etc.

Finally, here is an easy way to think of chord function and chord type: Chord function deals with what a chord does, chord type deal with how a chord is made. A chord function deals with what roll it plays in the harmonic movement of a song. A chord’s function depends on other chords around it. On the other hand, chord type deals with the relationship the notes of a chord have with each other independent of surrounding chords.

This discussion should give you an understanding of how chords work to influence feelings and how those chords are construction and arranged in songs. This knowledge will help you understand why a particular chord appears in a piece of music you are playing. It will also give you a framework for adding harmony to your own compositions. Still, harmony is only one of the elements you can use to engage and move the feelings of listeners. The other elements are rhythm, dynamics, melody, and timber. These will be topics of future postings. There’s more to come, but for now since you are a musician, I don’t need to tell you to stay tune!


NOTE: * Sometimes musicians will refer to the “third of a chord.” This is a bit ambiguous because they are not telling you if they mean a major third or minor third. Often the context in which they use the term will help. They might say, “the third of C Major Seventh (Cmaj7) is E.” You only know what note they are talking about if you already know that Cmaj7 is a major chord whose second note is a major third, not a minor third.


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