In music theory, a triad is a chord consisting of three notes. There are four main types of triads that are commonly used in Western music: major triads, minor triads, augmented triads, and diminished triads. Each triad type has a distinct sound and function within music. Understanding the four triad types is important for composers, musicians, and anyone interested in music theory.
Major Triads
A major triad is one of the most commonly used chords in Western music. It consists of the root note, the major third interval above the root, and the perfect fifth interval above the root. This creates a chord with a bright, happy sound. Major triads are built on the first, fourth, and fifth scale degrees of major scales.
For example, in the C major scale, the major triads are:
- C major triad: C, E, G
- F major triad: F, A, C
- G major triad: G, B, D
These are considered consonant, stable chords. Major triads create a sense of resolution and are used in chord progressions like the I-IV-V-I progression in many popular songs. Composers frequently use major triads as the tonic chord to establish the home key of a piece of music.
Major Triad Intervals
The intervals that make up a major triad are:
- Major third (4 semitones) – from the root to third
- Minor third (3 semitones) – from the third to fifth
So in a C major chord, there are 4 semitones from C to E, and 3 semitones from E to G.
Minor Triads
Minor triads have a somber, serious sound compared to major chords. A minor triad consists of the root note, the minor third interval above the root, and the perfect fifth interval above the root.
Minor triads occur on the second, third, and sixth degrees of the major scale. For example, in the C major scale, the minor triads are:
- D minor triad: D, F, A
- E minor triad: E, G, B
- A minor triad: A, C, E
These chords create tension and instability, driving the music forward. Minor triads are very common in minor keys. The minor triad built on the sixth scale degree is called the relative minor because it shares the same key signature as the major scale.
Minor Triad Intervals
The intervals that form a minor triad are:
- Minor third (3 semitones) – from the root to third
- Major third (4 semitones) – from the third to fifth
So in A minor, there are 3 semitones from A to C, and 4 semitones from C to E.
Augmented Triads
An augmented triad is a major triad with a raised fifth. This creates an unstable, dissonant sound. Augmented triads contain the following intervals:
- Major third (4 semitones) – from the root to third
- Augmented fifth (8 semitones) – from the third to fifth
For example, in the key of C, an augmented triad would be C, E, G#. The fifth (G) is raised by one semitone to G#. This chord contains a lot of dissonance and tension demanding resolution.
Augmented triads most often occur on the third scale degree in major keys. For example, in the key of C, the E augmented triad (E, G#, B) contains the raised fifth that creates the augmented sound. Composers use augmented triads for dramatic effect, to introduce unexpected tension in a piece.
Other Augmented Triads
While they mainly occur on the third scale degree, augmented triads can be built on any root note by raising the fifth. For example:
- C augmented – C, E, G#
- F augmented – F, A, C#
- Bb augmented – Bb, D, F#
These chords have a similar unsettled sound, though not as commonly used in traditional harmony.
Diminished Triads
A diminished triad is a minor triad with a lowered (flattened) fifth. This creates an unstable chord with a tense, dissonant sound. Diminished triads contain these intervals:
- Minor third (3 semitones) – from the root to third
- Diminished fifth (6 semitones) – from the third to fifth
For example, in C major, the diminished triad would be C, Eb, Gb. The fifth (G) is lowered by one semitone to Gb.
In major keys, diminished triads occur on the seventh scale degree. For example, in C major the B diminished triad (B, D, F) contains the flattened fifth. Like augmented chords, composers use diminished chords to introduce tension that pulls the listener towards resolution.
Other Diminished Triads
While they most often come from the seventh degree of the major scale, diminished triads can be built on any root by lowering the fifth:
- C diminished – C, Eb, Gb
- F# diminished – F#, A, C
- Bb diminished – Bb, Db, Fb
These chords have an unsettled sound and push towards resolution. Diminished triads are frequently used as passing chords in music.
Summary of the 4 Triad Types
Here is a summary of the four triad types:
| Triad Type | Intervals | Example in C | Sound |
|---|---|---|---|
| Major | R – Major 3rd – Perfect 5th | C – E – G | Stable, bright |
| Minor | R – Minor 3rd – Perfect 5th | C – Eb – G | Tense, serious |
| Augmented | R – Major 3rd – Augmented 5th | C – E – G# | Unstable, dissonant |
| Diminished | R – Minor 3rd – Diminished 5th | C – Eb – Gb | Tense, unsettled |
Triad Functions in Music
Beyond their unique sounds, each triad type also has specific functions within music harmony and chord progressions:
- Major triads – Stable, consonant chords. Often used as tonic and dominant chords.
- Minor triads – Create instability and tension. Used as subdominant chords or in minor keys.
- Augmented triads – Add dissonance and color. Used as a surprise chord.
- Diminished triads – Increase tension and lead to resolution. Used as a passing chord.
Understanding these functions allows composers to deliberately construct chord progressions to convey different emotions and harmonic movements.
Playing Triads on Piano and Guitar
Triads are very easy to play on piano and guitar. On piano, a triad is formed by playing notes from the root, third, and fifth degrees of a scale simultaneously. For example, a C major triad is built by playing C, E, and G together.
On guitar, triads are played by strumming the root, third, and fifth notes on adjacent strings. For example, a G major triad can be played by holding down the G note on the low E string with your index finger, then adding the B note on the A string with your middle finger, then adding the D note on the D string with your ring finger.
Learning common triad shapes allows guitarists to easily construct chords. There are open chord forms and movable barre chord shapes for major, minor, diminished, and augmented triads up and down the guitar neck.
Triads in Jazz Music
Triads are essential chord building blocks in jazz music. Seventh chords, ninth chords, eleventh chords, and thirteenth chords – common in jazz – are all constructed by starting with a triad then adding additional notes.
Jazz composers use triads derived from major, minor, and harmonic minor scales to create rich jazz harmonies. Altering one note in a triad, like changing the fifth to a flat fifth, can transform it into a jazz chord with unique color and function.
Guitarists use their knowledge of triad shapes to play jazz chords. For example, a guitarist can take a G major triad shape and flatten the fifth to play a G7 dominant seventh chord essential in jazz music.
Triads in Pop and Rock Music
Major and minor triads are widely used in pop and rock music, providing consonant accompaniment to melodies. Straightforward chord progressions using just triads, like I-V-vi-IV, are common in many rock and pop songs.
Power chords, frequently used in rock music, are built from only the root and fifth of a triad. Hard rock and metal bands often write riffs focused just on the robust, impactful sound of fifths without the added color of thirds.
Triads played on electric guitar with distortion provide the quintessential sound of pop and rock music. From The Beatles to Nirvana, countless artists have powered hit songs through catchy, triad-based guitar riffs and chord progressions.
Contemporary Music Styles and Triads
Though triads have a long history dating back to Medieval church music, they continue to feature prominently in the most modern music today. EDM producers frequently use plain major triads to create bright, euphoric builds in dance tracks.
Hip-hop producers sample chords from soul records, which often contain classic major and minor triad progressions played on piano or guitar. These sampled chords add harmonic depth beneath rapped vocals.
Even highly experimental styles like glitch and ambient make use of stripped-down triads for texture and color. Though the context always shifts, the essential major, minor, augmented, and diminished triads remain indispensable across all genres.
Learning Triads
For any musician, learning triad theory provides a crucial foundation for constructing chords and understanding harmony. Here are some tips for mastering triads:
- Study interval structure – memorize the semitone makeup of each triad type.
- Build triads in every key – practice playing and identifying triads on piano and guitar.
- Listen to examples – hear how triads sound and function in chord progressions.
- Apply in compositions – compose chord progressions using different triad types.
- Analyze music – determine what triads are used in your favorite songs.
A strong triad foundation will unlock your ability to understand, play, and create more advanced chords and harmonic music.
Conclusion
Major, minor, augmented, and diminished triads form the backbone of harmony in Western music theory. Though only three notes, these triad types each have a unique sound, function, and emotional impact. Understanding triads opens up possibilities for composers, improvisers, music analysts, and all musicians.
Triads continue to shape popular music today as much as classical and jazz masterpieces from past centuries. From arena rock singalongs to avant-garde soundscapes, triads find endless applications in the hands of creative musicians. So equip yourself with music theory knowledge and harmonic tools by learning the magic and versatility of triads.