Learn Guitar Lessons, Watch Videos, Join the Community

A triad is simply a chord built of 3 notes that are based on thirds.

The first thing we should notice is that there are 2 types of thirds:

2 Types of Thirds: Major 3rd -> 4 semi-tones Minor 3rd -> 3 semi-tones A semi-tone is the distance between 2 adjacent keys on a piano when counting both white and black keys. This measure can be referred to as an interval.

If we simply add two 3rds to a C note, we get the C Major triad.

C Major triad C E G 1 3 5 <- all Major triads will use this formula From C to E is a Major 3rd and from E to G is a minor 3rd

The numbers underneath the notes correspond to there value within a scale:

C Major Scale C D E F G A B C 1 2 3 4 5 6 7 1

If we use the same method only switch the order of the thirds we can get a minor triad. So, the first 3rd will be a Minor 3rd and the second will be a Major 3rd.

So lets take the C Major scale and create the C minor triad. We'll start with a minor 3rd and then add a major 3rd.

C Minor Triad C D# G 1 b3 5 <- all minor triads will use this formula Note that the first 3rd is flattened to create D# From C to D# is a minor 3rd and from D# to G is a Major 3rd

Lets stop for a moment and clarify a few things. Triads are made by adding thirds to the root note of scales (this would be C for the C Major Scale). There are 2 types of thirds...the major thirds and the minor thirds. When we add 2 thirds to the root note where the 1st is a major third and the 2nd is a minor third, we get a major triad. When the 1st third is minor and the 2nd is major, we get a minor triad. Hopefully this clears up any previous confusion.

Now for the last type of triad: Diminished. The diminished triad is formed by adding 2 minor thirds to the root note:

C Diminished Triad C D# F# 1 b3 b5 <- all diminished triads will use this formula Note that the thirds are flattened to create D# and F# From C to D# is a minor 3rd and from D# to F# is a minor 3rd

It's fairly simple to create triads with the following formulas:

Major Triad -> 1 3 5 Minor Triad -> 1 b3 5 Diminished Triad -> 1 b3 b5

From these formulas we can apply them to the corresponding major scales to get major, minor, and diminished triads.

if students have a hard time distinguishing the triad sounds, sometimes it helps to find a "connection" ie...the train sound is diminished....usually a funeral march is minor (though sometimes morbid) and majors are usually bright and cheerful sounding

....also, an "augmented" triad keeps 1 and 3 the same and raises the 5th by 1/2 step....sounds like something else ( usually the IV chord) is coming

I roll on triads.