Triad Chord Construction Part 3 - Diminished and Augmented Triad Chords for Guitar
OK, we have looked at the major and minor triads and we know that triadic chords are constructed from three notes. In the case of major, the three notes are the first, third, and fifth interval notes out of the scale from which the chord is constructed. The minor chord is constructed in the same fashion, except we flat the third interval note by moving it one-half step backwards or toward the nut. The diminished chord is similar to the minor. It contains a flat third, but also contains a flatted fifth interval. You will remember that our fifth interval in the C Major is a G on the open third string. How do we flat this string? Well, we can’t, so the open position C major chord is not an easy reference point for building a C diminished chord. We will be looking at some chord forms later, and we will see a way to convert to an alternate fingering pattern to allow for easier conversion of one chord type to another. At present we want to establish how chords are constructed, so just memorize the concept: start with the major and flat the third and fifth to get a diminished. For now, look at the A major chord, since we can easily “diminish” this chord in it’s open position form.
Remember that the A major scale contains a sharped C note at the third interval. When we flat the C#, this yields a C note, as you can see in the diagram. Here are the remainder of the diminished chords we can make in the open position. Notice the alternate symbols. You will see these symbols used interchangeably in other resources. Both indicate the diminished chord. We will look at the G diminished later when we get to moveable chord forms.
Now, let's look at the augmented chords. Back to C major as reference, let’s raise the fifth interval by a half step for a sharp 5. G is our fifth interval note in the C major triad, played on the third string open. So let’s fret the third string, 1st fret to get our sharp five:
Strum that one a few times and you will be able to hear the “augmented” sound. Sounds kind of tense, doesn’t it, like you need to change it to something else? That’s how augmented chords are used, as a tense transitional chord to add a sense of urgency toward chord movement. We will look at that concept some more when we get to progression construction on the next page.
Here are the rest of the augmented triads in the open position. Notice the alternate symbols, for example A aug and A+. You may see either one of these symbols used to identify an augmented chord.
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