Introduction to Triads

Introduction to Triads

Chapter 7

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Chords and Triads

In music, a chord is two or more intervals sounding together. The notes in a chord may sound all at once or appear in succession, creating an arpeggio.​

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A specific type of chord is the triad, a three-note chord that combines two 3rds, one above the other. Every triad must contain a root, third, and fifth.

Triad Components

In every triad, there is an interval of a 3rd between the root and the third. There is another 3rd between the third and the fifth. Finally, there is a 5th between the root and the fifth.​

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If they are in root position, meaning the root is on the bottom, they will usually be three successive lines or three successive spaces (see picture on the right).

Intervals in Triads

Look at the picture on the right to see how a root position triad is made up of a third stacked on top of a third, leaving an interval of a fifth between the root and the fifth.​

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Be careful not to get confused between the intervals used to make the triad (i.e. 3rd and 5th) and the names of the triad (i.e. root, third, and fifth).

Triad Qualities

Triads are named by the letter of their root and the quality of the chord. There are four qualities for triads.​

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Major triads contain the following intervals:

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• M3 between root and third

• m3 between third and fifth

• P5 between root and fifth

Multiple Choice

Which of the following intervals is NOT found in a major triad?

• M3 between root and third

• m3 between third and fifth

• M3 between third and fifth

• P5 between root and fifth

Major Triads

Let's check one together. First, we see what the quality of the 3rd is between the root (A) and the third (C#). In the key of A major, we have 3 #'s, including C#. That means A to C# is a M3. So far so good!

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Next, we check the quality of the 3rd between the third (C#) and the fifth (E). In the key of C# major, we have 7 #'s, including E#. That means C# to E is a m3. Again, this points to a major triad.

Let's check our work

To check our work, we measure the root (A) to the fifth (E). In the key of A major, we have 3 #'s, and none of them are E#. Therefore, A to E is a P5.​

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If our triad has a M3 with a m3 on top, and we have double checked that the root and fifth form a P5, it is a major triad.

Multiple Select

The following chord is a major triad.

• True

• False

Multiple Select

The following chord is a major triad.

• True

• False

Multiple Select

The following chord is a major triad.

• True

• False

Triad Qualities 2

Minor triads contain the following intervals:​

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• m3 between root and third

• M3 between third and fifth

• P5 between root and fifth

Multiple Choice

Which of the following intervals is NOT found in a minor triad?

• m3 between root and third

• M3 between third and fifth

• m3 between third and fifth

• P5 between root and fifth

Minor Triads

Let's check one together. First, we see what the quality of the 3rd is between the root (C) and the third (Eb). In the key of C major, we have 0 b's. That means C to Eb is a m3. So far so good!​

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Next, we check the quality of the 3rd between the third (Eb) and the fifth (G). In the key of Eb major, we have 3 b's, none of which are Gb. That means Eb to G is a M3. Again, this points to a minor triad.

Let's check our work

To check our work, we measure the root (C) to the fifth (G). In the key of C major, we have 0 #'s and 0 b's, which means G fits the key signature. Therefore, C to G is a P5.​

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If our triad has a m3 with a M3 on top, and we have double checked that the root and fifth form a P5, it is a minor triad.

Multiple Select

The following chord is a minor triad.

• True

• False

Multiple Select

The following chord is a minor triad.

• True

• False

Multiple Select

The following chord is a minor triad.

• True

• False

Triad Qualities 3

Diminished triads contain the following intervals:​

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• m3 between root and third

• m3 between third and fifth

• d5 between root and fifth

Multiple Choice

Which of the following intervals is NOT found in a diminished triad?

• m3 between root and third

• m3 between third and fifth

• d5 between root and fifth

• P5 between root and fifth

Diminished Triads

Let's check one together. First, we see what the quality of the 3rd is between the root (A) and the third (C). In the key of A major, we have 3 #'s, including C#. That means A to C is a m3. So far so good!​

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Next, we check the quality of the 3rd between the third (C) and the fifth (Eb). In the key of C major, we have 0 b's. That means C to Eb is a m3. Again, this points to a diminished triad.

Let's check our work

To check our work, we measure the root (A) to the fifth (Eb). In the key of A major, we have 3 #'s, none of which are E#. Therefore, A to Eb is a d5.

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If our triad has a m3 with another m3 on top, and we have double checked that the root and fifth form a d5, it is a diminished triad.

Multiple Select

The following chord is a diminished triad.

• True

• False

Multiple Select

The following chord is a diminished triad.

• True

• False

Multiple Select

The following chord is a diminished triad.

• True

• False

Triad Qualities 4

Augmented triads contain the following intervals:

• M3 between root and third

• M3 between third and fifth

• A5 between root and fifth

Multiple Choice

Which of the following intervals is NOT found in an augmented triad?

• M3 between root and third

• m3 between third and fifth

• M3 between third and fifth

• A5 between root and fifth

Diminished Triads

Let's check one together. First, we see what the quality of the 3rd is between the root (E) and the third (G#). In the key of E major, we have 4 #'s, including G#. That means E to G# is a M3. So far so good!​

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Next, we check the quality of the 3rd between the third (G#) and the fifth (B#). There is no such thing as the key of G#. However, if we pretend each note is a half step lower, G# to B# becomes G to B. The distance between them is the same. The key of G has 1 # (F#). That means G to B is a M3, and G# to B# is a M3. Again, this points to an augmented triad.

Let's check our work

To check our work, we measure the root (E) to the fifth (B#). In the key of E major, we have 4 #'s, none of which are B#. Therefore, E to B# is an A5.​

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If our triad has a M3 with another M3 on top, and we have double checked that the root and fifth form an A5, it is an augmented triad.

Multiple Select

The following chord is an augmented triad.

• True

• False

Multiple Select

The following chord is an augmented triad.

• True

• False

Multiple Select

The following chord is an augmented triad.

• True

• False

Lead Sheet Symbols

Since triads are named after their root and their quality, we can use lead sheet symbols (also known as pop chord symbols) to shorten their names. There are several variations for each quality, but a few of the most common are listed below. Let's use the root C as our example.​

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C major or C

C minor or Cm or C- or c

C dim or C^o

C aug or C+

Example 7.3 (comparison of the four triad qualities built on F)

Multiple Choice

What quality is the following triad?

• Major

• Minor

• Augmented

• Diminished

Multiple Choice

What quality is the following triad?

• Major

• Minor

• Augmented

• Diminished

Multiple Choice

What quality is the following triad?

• Major

• Minor

• Augmented

• Diminished

Multiple Choice

What quality is the following triad?

• Major

• Minor

• Augmented

• Diminished

Multiple Choice

What quality is the following triad?

• Major

• Minor

• Augmented

• Diminished