The Most Essential Chord: What is a Triad?

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Welcome to, I’m Robert Estrin. The subject today is about triads. What is a triad? A triad is the most basic chord that exists in music. I’m going to break it down for you, so you’ll have a keen understanding of what a triad is. Simply put:

A triad is a chord containing three notes arranged in thirds.

What is a third? Scales are built diatonically. That means interval of seconds. So each note of a scale is a second apart. If you skip a note in a scale, you have a third. Anytime you skip a note in a scale, it’s a third. In fact, anytime you go from one letter and skip a letter and go to another letter, that is some type of third. Fortunately, there are only two types of thirds that are used in triads. And by the way, there are only two types of thirds that are used in the vast majority of chords. Believe it or not, even sophisticated chords can all be broken down to some type of thirds.

In triads, you have two types of thirds: major thirds and minor thirds.

To make things easy for you, I’m going to explain what they are in the simplest possible terms. Once again, they’re always two letters that are separated by another letter. A major third is a total of four half-steps. So if you start on middle C and count up by four half-steps to E, that is a major third. It’s very simple. A minor third is smaller. It’s only three half-steps. So once again, start on middle C, but this time count up by three half-steps to E-flat. That’s a minor third. That’s basically those are the building blocks of Western harmony, in a nutshell. You can actually figure out just about all chords by simply arranging the notes in thirds. Sometimes they are inverted. I’m going to get to that in a little bit. But first, let’s get to the basics.

You have four possible arrangements.

As I said, a triad contains three notes arranged in thirds. So you have a root, a third, and a fifth. So you have two sets of thirds. If you have a major third on the bottom and a minor third on top, that is called a major triad, for example, C – E – G. If you reverse it and have a minor third on the bottom and a major third on the top, that is a minor triad which would be C – E-flat – G. Could you call the middle note, D-sharp? No. Why? Because all chords are spelled in thirds skipping letters between each note of the triad.

If you have two minor thirds, that’s a diminished triad. Why is it called a diminished triad? Because the fifth has become diminished. Instead of the perfect fifth, which is the fifth note of the scale, C to G, it’s now a half-step smaller C to G-flat. So the triad is spelled, C – E-flat – G – flat. The diminished triad has two minor thirds. Finally, two major thirds is an augmented triad because the fifth has become augmented, C to G-sharp. It has become larger by a half-step. The augmented triad is spelled C – E – G-sharp.

Triad Scales

Scales 2

Now here’s where it gets interesting.

If you had, for example, a C-sharp major triad, once again, a major third on the bottom and a minor third on top, you start on C-sharp and go up by four half-steps. What is that note? Is that F? Well, it can’t be F because triads are built in thirds. Thirds must skip every other letter. So it has to be an E-sharp. Why would it be spelled that way? Isn’t that confusing? Quite the opposite. If you saw this written C-sharp, E-sharp, G-sharp in your score, it would look like a triad. If you saw C sharp, F, A-flat, or something of that nature, it wouldn’t look like a chord anymore. You wouldn’t recognize it as a chord. When it’s written correctly, you just see all the notes thirds apart, and it clicks that it is a triad.

You can figure out any major, minor, diminished, or augmented triad using this method.

Just remember they always must skip letters, and there are four combinations. To recap, a major triad has a major third on the bottom and a minor third on the top. Switch it up, and you get a minor triad, with the minor third on the bottom and the major third on top. Two minor thirds make a diminished triad. Two major thirds make an augmented triad. Triads are always spelled in thirds.

Keep in mind that triads are not always in root position.

That means that the root of the chord isn’t always on the bottom. So if you had a C-major triad and the E was on the bottom and the C was on top, this is still a C-major triad. How do you know this? You take the letters and arrange them in thirds, and that’s how you find the root of the chord. Understanding this will help you figure out harmonies, learn music, read more effectively, and improvise. All of this is great practice for you! Thanks again for joining me, Robert Estrin, here at, Your Online Piano Resource.

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