We’re at the final stop on our journey through triads. We’ve already discussed major, minor and diminished triads. In this installment, we’re going to look at augmented triads. You may recall from the previous lesson that major and minor triads are the most common triads, with diminished and augmented triads being a little more rare.
I tend to think of major and minor triads and being paired together. I also think of diminished and augmented triads as being paired together because of their decidedly non-major/minor sound. Both have a very “outside” kind of sound, but that doesn’t mean that diminished and augmented triads are interchangeable. They have very different sounds.
Let’s start by defining what an augmented triad is—it’s a triad formed by two major thirds. You can also think of an augmented triad as being composed of the root, major 3rd and augmented 5th. Remember that “augmented” means a note raised a half-step (one fret).
In the key of A, the augmented triad would be A (the root), C♯ (the major third) and E♯ (or F, the augmented fifth). The augmented triad is closest to the major triad. The only difference between the two is the fifth, which is a half-step (one fret) higher in a diminished triad.
Here are the neck-shapes for augmented triads in A:
The augmented shapes are little different from the other ones we have looked at so far. Notice that no matter which note of the triad you start on, the augmented triad is the same shape going up and down the neck!
Why is this? Remember in our discussion of intervals that another name for the augmented fifth is the tri-tone, which we know is the exact half-way point between a note and the octave above it. Since the interval between the augmented fifth and major third is the same as the distance between the root and the major third, the augmented triad is completely symmetric.
Now here’s the funny thing about diminished triads, the same notes can actually be used for three different triads. The C♯ augmented triad is made up of C♯ (the root), F (the major third) and A (the augmented fifth). Whoah. Look at that! It’s the same three notes as the A augmented triad. The same thing goes for the F augmented triad (I’ll leave it to you to work out the math).
If this doesn’t make sense at first glance, try working the notes in each augmented triad shape above to prove this little numeric fact to yourself.
So with the theory and shapes covered, the next question you should be asking is, how do I use these?
In rock, the augmented triad doesn’t show up too often. Even in the chord-rich world of jazz, the augmented triad is a very exotic visitor from a foreign land, though you will hear the augmented sound in a lot of fusion (e.g. Allan Holdsworth).
One place that you’ll hear the augmented 5th interval is in rock power-chord progressions like this:
That augmented fifth interval isn’t strictly an augmented triad. If you tried to add the thirds to these power chords, it doesn’t sound very good:
Now as a straight-ahead rock guitarist, you may not have a lot of practical use for augmented triads. But it doesn’t hurt to know about them, especially in relation to the other triads. Why throw away perfectly good knowledge?
You may also find that once you get the shapes under your fingers and the sound in your ears, that you start mixing a little of the “outside” sound of augmented shapes into your repertoire. Augmented triads are closely related to the whole-tone scale, which is a topic I’ll cover in the future.
That’s all for now. With triads under our belt, we can start looking at chords. The most basic chords, are essentially triads with extra notes. But as we start looking at more sophisticated chords, you can still see the load-bearing triads that support them.