What Is A Triad? Triads In Music Theory For Guitar

What Is A Triad? Triads In Music Theory For Guitar

There are only four triads in music: major, minor, augmented and diminished. They are 3-note chords built with different qualities of their 3rd and 5th chord tones.

Major triads are the most commonly used followed by minor triads. Diminished triads are used less often in popular music than major or minor triads. Augmented triads are the least common.

Their construction is easy to understand and is fundamental to understanding more complex chords that are built using the triads.

 

What is a triad?

The first thing to learn in music is the single notes of the chromatic scale. Next, you should learn all of the music intervals. Then there are the 3 notes that make up the four types of triads in music.

Practically every chord with 4 or more notes is just one of the four triads with additional notes. Triads in music are the basis for harmony.

Triad definition

A triad is a group of three notes where the second note is a third away from the first note, and the third note is a third away from the second note. The first note is called the “root”, the middle note is the “third” and the final note is the “fifth”.

There are 2 kinds of thirds: major and minor. A minor third is the distance of 3 half-steps, where a major third is 4 half-steps. If you do not know what I mean by “thirds” or “fifths”, then take a look at my article on music intervals.

So a triad is two successive third intervals, and since there are 2 types of thirds there are four possible combinations:

1. major third + major third

2. minor third + minor third

3. major third + minor third

4. minor third + major third

Those four combinations of thirds create the only 4 triads in music: major, minor, augmented and diminished triads. I’ll cover each one below, but I want to compare them to each other:

  • Major & minor triads both have perfect 5ths.
  • Augmented and diminished triads both have altered fifths.
  • Major and augmented triads both have major thirds.
  • Minor and diminished triads both have minor triads.

Let’s look at each one separately.

 

The four types of triads: major, minor, augmented & diminished

 

Major triads

If you are only going to learn one type of triad, then it should be the major triads. There are many songs that only have major chords. Major triads have an unmistakable upbeat and lively sound.

The major triad:

  1. Has a major 3rd above the root followed by a minor 3rd
  2. The interval symbols are M3 + m3
  3. Contains the root note + major third + perfect fifth
  4. Usually notated as 1-3-5 or R-M3-P5

Intervals of the C major pentatonic scale

Example: C major = C – E – G

 

Minor triads

Minor triads have a more mellow sound than the major triad, and some people would say they have a somber sound. The majority of popular songs use a combination of major and minor triads.

Example of triads in music: a minor triad

The minor triad:

  1. Has a minor 3rd above the root followed by a major 3rd
  2. The interval symbols are m3 + M3
  3. Contains the root note + minor third + perfect fifth
  4. Usually notated as 1-♭3-5 or R-m3-P5

Example: C minor = C – E♭ – G

I include closed and bar chord versions of the major and minor triads in other articles.

 

Augmented triads

Augmented triads are not as common in popular music as the other three triads. I feel the augmented triad have an open or hollow sound to them, and I do not mean that in a bad way.

I find that they are best arpeggiated as opposed to strummed like other triads. They have a unique sound that you have to hear for yourself.

Check out the Wikipedia page on augmented triads if you want to learn more. This is just a quick music theory article covering the fundamentals.

The augmented triad:

  1. Has a major 3rd above the root followed by another major 3rd
  2. The interval symbols are M3 + M3
  3. Contains the root note + major third + augmented fifth
  4. Usually notated as 1-3-#5 or R-M3-A5

Example: C aug or C+ or C#5 = C – E – G#

 

Diminished triads

Diminished triads are interesting in that they contain the interval of the tritone, otherwise known as the “diminished” fifth. The diminished triad is a very dissonant chord because of the tritone interval.

As a result, this triad wants to resolve up a semitone to the tonic of the song. For example, Bdim resolves very smoothly to C major. Check out the Wikipedia page on diminished triads if you want to learn more.

The diminished triad:

  1. Has a minor 3rd above the root followed by another minor 3rd
  2. The interval symbols are m3 + m3
  3. Contains the root note + minor third + diminished fifth
  4. Usually notated as 1 – ♭3 – ♭5 or R-m3-d5

Example: C dim or Co = C – E♭ – G♭

Here are the two classic augmented and diminished triad guitar shapes. The black slash for the last diminished triad is an optional root if you can mute the 5th and 4th strings. The white circles are the root note, the numbers are your fingers (1 = index, 2 = middle, 3 = ring, 4 = pinky).


4th string root of an augmented triad
5th string root aug chord
5th string root dim triad
Diminished triad

 


 

Sus4, sus2 & majb5: the other “triads” \ chords in music

There are other 3-note chords used in popular songs that are not one of the triads in music.

The first two are suspended chords where the third of the triad is replaced either by the perfect fourth (most common) or the major second.

Suspended chords: sus4 or sus2
sus4 = 1-4-5, the root note followed by the perfect fourth and then the perfect fifth (R-P4-P5)
sus2 = 1-2-5, the root note followed by the major second and then the perfect fifth (R-M2-P5)

Example: Csus4= C – F – G, Csus2 = C – D – G

Note: Gsus4 = G – C – D, and in first inversion the notes are C – D – G – the same notes as a Csus2.

The last 3-note chord is the major flat five, notated as majb5. Personally, I do not use this chord nor do I have any chord shapes for it. I include it here for two reasons:

1. There is a maj♭5 chord in the song Great Gig In The Sky by Pink Floyd. If that chord is okay with Roger Waters, then it’s okay with me.

2. The 1-3-♭5 are the first three notes in every 7b5 chord, so it is definitely worth mentioning.

Majb5 = 1-3-♭5, the root followed by the major third and then the diminished fifth (R-M3-d5).

Example: Gmaj♭5 = G – B – D♭

Summary

The four most basic fundamentals in music are the chromatic scale, music intervals, the four types of triads, and the major scale. The last two are the most practical.

You use the major scale to improvise over a song, but a song needs to have chords in it to solo over. It’s the triads in music that are used to create the chord progressions of songs.

Once you understand the triads in music, then you can add other notes to them to build more complex chords. You use scales like the major scale to create 4, 5 and 6-note chords for more complex harmonies.

But when you strip away all the adds, sevenths, and extensions, you will find the triads are the heart of all harmony. You need to understand how to build and use all the triads in music. You won’t be asked to join a band if you don’t know what a diminished or augmented chord is. The choice is yours.

 

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