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Guitar And Chord Construction

By Tim Gillespie

How To Construct Chords

A complete discussion of chords could not go far without including the subject of intervals. In order to understand chords, you must understand intervals. So this month, our discussion will start with intervals.

Intervals are the spaces between notes. The distances you travel to sound the next note in either a scale run or a chord. Since the smallest possible chord, the triad, must contain at least three notes, there are at least two intervals present. Three notes in the chord, two spaces between notes.

It is intervals that determine if a chord, in a standard diatonic key, is either major, minor or diminished. These are three of the four possible combinations of a standard triad in a diatonic key.

So let's look at a diagram of chords in the key of C. This is the same diagram that appeared in the October issue.

We are going to build on this information in a minute. But first let's take a look at what happens if you stack different combinations of major and minor thirds.

Our discussion of intervals is going to be limited to thirds this month because chords are created by stacking thirds. A third is the distance between three notes in a standard diatonic scale. Look at the first set of notes in the example to the left. The gray notes are C, E and G. These are the notes in the C major triad. Look at the spaces between the notes.

The distance between C and E is a third. If you travel four frets you create a major third. C to E is a major third. Now notice the distance between E and G. The distance is three frets. This is a minor third. If you travel one more note you will hit the F note. The interval created by traveling from C to F, is called a fourth. You are traveling four degrees in the scale of C. But for now, we are only concerned with thirds.

So the third, can either be major or minor. There are no other choices. If a third is four frets apart, it is a major third. If the third is three frets apart, the third is minor. The lower third in a chord is the third created by moving from the first note to the third note. In this case C to E. The upper third is between the third and fifth note, E to G.

Look at what happens to a C major chord if you change the lower third (C to E) to a minor third. If you flat the E, the lower third (C to Eb), would then become a minor third. The upper third (Eb to G), would then be a major third.

You can also describe Eb as a D#. That is an example of an enharmonic spelling. The same note has two names.

Of course the notes C, Eb, G are the notes of C minor. Notice this example is exactly the same as C major, except the E has been flatted.

The overwhelming point of this illustration is the third degree determines weather a chord is major or minor. Look at the illustration of the chords in the key of C major above. Notice the one, three and five degrees are gray. They are the notes in the chords.

Now notice the third is the only one that changes, (except for the B diminished chord). Now remember how the flow of chords in the key of C goes. Consult the table below. Notice the one, four and five chords are major and the lower thirds are all major. Notice the two, three and sixth chords are minor chords and all have a lower third that is minor. Notice the seventh chord has two minor thirds stacked on top of one another. This creates a diminished triad.

The third is the important note in determining whether a chord is major or minor.

Below are three examples of chord types. We are not discussing the fourth type of chord, the augmented chord, because it does not occur in a standard diatonic key. You must examine the harmonic form of the minor scale before you will see an augmented chord.

So What?

Now we know how to construct chords in the key of C. It is actually very helpful when designing a song to have and use this information. Songs are usually key based. This means a song in the key of C will have lead or melody lines constructed of the C major scale. And the chords that will create the rhythm section are usually the chords found in the key of C. That is the palate for the song. You then start to combine the chords in different arrangements to create the base of the song.

So if you are interested in building a song in the key of C, here are the chords that you can use. Keep in mind there are several variations of each of these chords to choose from. These are the some of the most basic forms.

You can also turn the basic chords into seventh chords and substitute any of these seventh chords for the basic chords. Instead of using a C major chord, you can substitute the C major 7 chord. Could you substitute the C 7 for the C major chord (instead of the C major 7 chord)? Yes you can, but there is one big difference between C 7 and C major 7. The C major 7 chord uses only the notes in the key of C. The C 7 chord includes a Bb, which is outside of the key of C. If you use the C7 chord, you are violating the key of C. No problem, as long as that is what you wanted to do. The Bb note will stick out and it may seem out of place. All of the chords in the pink example below, use notes inside the key. None of these chords will violate the key of C.

 

Progression in the key of C major.

So now that you know how to create chords in the key of C, here are some combinations.

The I, IV, V progression.

 

The I, VI, II, V, I progression.

 

The I, V, IV, II, III, VI progression.

 

As I have stated, you can also substitute a seventh chord for any of these basic chords. Here are a few examples.

Instead of a I,V combination, you can play a I,V7.

The I, V progression.

 

The I, V7 progression.

 

Here are a few more combinations.

The I, V7, IV progression.

 

The I, II, V7, I progression.

The power of chords is in knowing what to do with them. All of these chords are great for songs in the key of C and each one has a personality of it's own. All of these chords will contain only the notes in the key of C and that is helpful when constructing a solo to fit on top of a progression in C major. To construct a solo over these chords, you only have to go to the C major scale.

The C major scale will work with any of these progressions. The better you know the C major scale, the faster you can create a workable solo. If you can play the scale already, you may be able to just modify it and construct a solo on the spot.

Parting thoughts.

Notice the sixth chord in the key of C is the A minor chord. Also notice some of these progressions will use the A minor. This chord provides an opportunity to switch to another key in mid-song.

Often times a song will go along in the major key and then all of the sudden, the progression may center around the relative minor. In this case it is the A minor. The A minor will then act as a bridge to the next part of the song. The song may then use the chords in the minor key and with a change of timing, this may change the entire feeling of the song. It can trick your ear. You may notice the change, but putting your finger on what happened can be difficult.

The chords are still in the key of C, but now they are arranged around the relative minor chord. This is very common in the typical songs you hear today. It is an easy trick to inject a new sound and a new direction in a song. Soloing in the scale of C major will still work, but now the C note will not bring the piece to rest, now the A note will do that and serve as tonic.

Keep in mind there are three different version of the A minor scale, the natural, the harmonic and the melodic signature. In the natural form, there is no change in the scale and chords, but in the other two forms, there are subtle differences that change the whole key. And that is the subject of next month's discussion.

These chord diagrams are taken from Uncle Tim'seChord Chart.