Estimated reading time 5 minutes
Table of Contents
Introduction
“Can somebody please help me understand these stupid triads?” Triads are one of the foundations of Western music theory (along with melody, rhythm, counterpoint, and orchestration). Understanding them will unlock your ability to both appreciate and write music. Keep reading An Easy How to Guide to Understanding Triads to learn how they work.
This article uses musical terms. For definitions, see the Glossary at the end of the post.
Understanding Triads: What’s a Triad?
Triads are three note harmonies and are built using intervals called thirds. For example, the G major triad has:
- Root = G
- Third = B
- Fifth = D
The root is the note that the chord is named for:
- For example, G is the root of G major.
- The third is three notes above the root.
- The fifth is five notes above the root.
Therefore, the notes of G major are G B D. (See the chart below.)
Mobile users: for best results reading the examples, tilt your screen 90o to the right.
Root Position Harmonies in C Major
C Major Harmonies:
Understanding Triads: What’s a Chord Progression?
Notice in the chart above that there are seven distinct harmonies in the key of C major:
- When you change chords, you call it a chord progression.
- Chord progressions will often be associated with particular styles of music.
- For example, the 12 bar blues progression in C major will have: four bars of C, two bars of F, two bars of C, one bar of G, one bar of F, and two bars of C.
Roman numerals are used to analyze chord progressions:
- A Roman numeral indicates the note on which a harmony is built.
- Capital Roman numerals indicate major chords.
- Lower case Roman numerals indicate minor chords.
For more information on Roman numeral analysis:
- Can Someone Explain Roman Numeral Analysis in Layman’s Terms for Me?
- Tonic vs. Root in Music Theory
- What Exactly Does I7-vi7-V7 Mean?
- What’s the Deal with These iv-V-VII Chords and Stuff?
In piano/guitar/vocal scores, you’ll usually find chord symbols.
- In the chart above, the letter indicates a major chord, so C will be C major.
- A small “m” after the letter indicates a minor chord, so Dm will be D minor.
- A small “o” after the chord indicates a diminished chord, so Bo will be B diminished.
Understanding Triads: What Are Inversions?
Triads do not always have to have the root as the bottom note:
- You can arrange the notes in any order you want.
- If the note on the bottom of the chord is not the root, you call it an inverted chord.
- If the root is the bottom note, it’s in root position.
- If the third is the bottom note, it’s in first inversion.
- If the fifth is the bottom note, it’s in second inversion.
First Inversion Harmonies in C Major
Second Inversion Harmonies in C Major
Notice that in the two inversion-charts above, there are decimal numbers next to the Roman numerals:
- These are used in the analysis system called figured bass.
- Figured bass goes back to the Baroque period and uses numbers that represent intervals to indicate the inversions.
- In the second inversion chart the 4 should be below the 6, but the program couldn’t do that so they’re side by side.
How does figured bass work for triads?
- If there is no number, that indicates a root position triad.
- A 6 indicates first inversion.
- A 6-4 indicates second inversion.
The lead sheet chord symbols can also indicate the inversion:
- The letter to the left of the “/” is the triad.
- The letter to the right of the “/” is the bass note.
- A bass note is the lowest note in a chord.
Of course, the charts here only show you one key: C Major. For information on other keys:
Understanding Triads: How Many Types Are There?
To access an online keyboard: click here.
There are four categories of triads, and each has its own special tone quality.
Major Triads:
- They have a major third on the bottom of the chord and a minor third on the top.
- Also, they have a bright or happy tone quality.
- Major triad = major third (4 half steps*) + minor third (3 half steps)
Example: G Major = G B D
Minor Triads:
- They have a minor third on the bottom and a major third on the top.
- These harmonies have a dark or sad sound.
- Minor triad = minor third (3 half steps) + Major third (4 half steps)
Example: G Minor = G Bb D
With both major and minor triads, the bottom third defines the sound of the chord.
Diminished Triads:
- They have two minor thirds, which when stacked together makes a diminished fifth.
- These harmonies are tense, and the notes of the fifth need to resolve by half step in the opposite direction from each other. This chord sounds bad when unresolved (which is good for dramatic music) but sounds good if resolved correctly.
- Diminished triad = minor third (3 half steps) + minor third (3 half steps)
Example: G Diminished = G Bb Db
Augmented Triads:
- They have two major thirds, which when stacked together makes an augmented fifth.
- The augmented triad is the opposite of the diminished triad in that, while it is dissonant, it doesn’t have a strong tendency to resolve to another chord. It’s most often associated with the whole tone scale.
- Augmented triad = major third (4 half steps) + major third (4 half steps)
Example: G Augmented = G B D#
The sound of both the diminished and augmented triads are defined by the interval of a fifth within each chord.
* A half step is the distance from one key to the very next key on the keyboard – whether black or white.
Final Thoughts
Here are some find thoughts on triads:
- Triads help to make musical arrangements sound fuller and more interesting.
- The harmonies both support and influence the main melody.
- The trick to understanding them is learning how they’re constructed and how they work within a key.
For more information on writing them:
Have fun writing!
Related Posts
- Chord Progressions (Including the 12 Bar Blues)
- The C Major Scale (Including the C Major Chord Scale)
- D’you Want Some Music Tips and Tricks I’ve Learned Over the Years?
© 2024 Geoffrey Keith
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