|Basic Harmony - (Chord Construction)
All chords have, as their basic foundation, a triad. Triads are three-note chords, which can be major, minor, augmented or diminished in quality. All other chords are built on these basic three-note chord structures. That is, the 7th, 9th 11th, 13th and any altered notes are added on to one of the basic triads.
Triads are derived from major, minor, dominant or other scales. They are built on the root of the scale, which is the first note. That root, or tonic note, is given the number 1. So the root of the chord is also called the 1st of the chord.
Next, we skip the second note of the scale and select the third as we build our triad. That note is called the 3rd of the chord. Finally, we skip the fourth scale note and select the fifth. Adding that on top of the stack of notes, we call it the 5th of the chord.
So the notes of a triad, from the root up are the 1st, 3rd and 5th of the chord. Here's what that looks like.
The notes of the triads can be stacked up in order starting with the root - called root position (i.e. 1-3-5). They can also be stacked with a note other than the root on the bottom - called an inversion. If the 3rd of the chord is on the bottom, it is in first inversion. If the 5th is on the bottom, it is in second inversion. The inversions of a G Major triad are illustrated in the diagram below.
When the notes of a chord are stacked up in order, as was listed above, it is said to be in closed position. But the notes of a triad don't have to be in order. You can skip one note of a chord and place it an octave higher or lower in the chord stack. Instead of 1-3-5. 3-5-1 and 5-1-3, all in closed position, you can have 1-5-3 skipping the 3rd and placing it on top, an octave higher. You can also build a triad stacking 3-1-5 and 5-3-1, from the bottom up. When you build chords this way, they are called open-position chords. Look at the following diagram to see how that works.
Finally, when you build a triad, you can double one or more of the notes. Play a 6-string E major chord at the nut. Since you are using all of the strings, you must be playing 6 notes, right? But you are only playing three unique notes, with the root (E) doubled - twice! (It's found on the 6th, 4th and 1st strings. The 5th of the chord (B) is also doubled, found on the 5th and 2nd strings. So essentially you only have the 1, 3 and 5 (E, G# and B, respectively) of the chord present. Here it is.
Doubling is a way to play a basic triad and still get a bigger sound.
That's it in a nutshell. Of course there is more to it than the very brief explanation given above, but this will get you started. You would do well to look at Blues You Can Use Guitar Chords of some other book on harmony (particularly one aimed at guitarists) if this is totally new to you. You'll gain a much better understanding if you work through them step-by-step.
The most time consuming part of the study of harmony is in gaining a working knowledge of chords. That is, where they are on the fingerboard and how they move from one to the other, and being able to spot and grab them immediately. That's what we'll be looking at now and in the coming months.
Now go to the Major Triads and pages to see some useful examples of major triad voicings.