Chord Theory - Triads
Last time we used the harmonized scale to locate key centers, so now let’s examine how those chords in the harmonized scale are built. Understanding this will allow you to build any chord you need, even if you have not played it before, as well as show you know what notes are in the arpeggio.
To start with, all chords are built from four basic triads; major, minor, augmented and diminished. To build the major chord, you take the first or root, third and fifth notes from the scale with the same name. For instance a C major chord consists of the notes C, E and G, the first, third, and fifth notes of the C Major scale.
The same idea applies to the minor; take the root, flatted third and fifth from the scale of the same name. For Cm this would give us C, Eb, and G. Notice that the flatted third is the only difference here. This is important both in improvising and in chord construction. When building larger more complex chords, you may need to drop some notes. The third should not be left out as that is how you determine whether the chord is major or minor. As an improviser, the bass player often plays the roots and fifths, so the third will be a good note choice.
The augmented chord consists of the root, third and sharped fifth out of the scale of the same name. C+, (the plus is used for augmented and you will also see this written as Caug), would be C, E, and G#. Notice that like it’s name, the augmented chord stretches the root, third and fifth as far apart as possible.
The last of these is the diminished triad. We will refer to it as the diminished triad here as many people often use diminished to also refer to the diminished seventh chord. The diminished triad consists of the root, flatted third, and flatted fifth of the scale. For C°, (also written Cdim), this would be C, Eb, and Gb. Like the augmented, the name tells you what is happening here. The root, third, and fifth have been pushed as close together as possible.
Take some time and try these out on your instrument. Play each one and hear how they differ from each other and what kind of "mood" they create. Play them as chords in as many inversions as you can on a chordal instrument. On single note as well as chordal instruments, play the arpeggios in as many inversions and octaves as you can. Also try playing one after the other on the same root. For instance play C, then Cm, then C+ and then C°. Play them on each type through the circle of fourths. The more patterns you can come up with the better. Having a good solid understanding of these will make building larger more complex chords much simpler.