Unit 5 : Triads
Mr. Jackson
AP Music Theory
TRIADS
A TRIAD is a three-note chord (built like a snowman) made up of two intervals stacked in thirds.
Tertian Harmony – built on thirds!
TYPES OF TRIADS
 There are four possible ways to combine major and
minor 3rds to produce a tertian triad.
TYPES OF TRIADS
+
(Augmented)
Major
minor
dim ()
(Diminished)
TYPES OF TRIADS (SOUND)
Each triad has a different SOUND CHARACTERISTIC.
Sounds
Sounds
Sounds like
Sounds like
HOW TO BUILD A TRIAD
1. Build the “snowman” in thirds above the root. Tertian harmony thirds will either be all lines
or all spaces!
2. Identify the quality of the lower third as major or minor.
3. Identify the quality of the fifth (between the root of the triad and the fifth) as perfect, diminished, or
augmented.
 You can also identify the quality of the upper third as major or minor (between the third of
the triad and the fifth.)
4. Identify the chord with a letter (the root of the “snowman”.)
5. Identify the quality of the triad:
 M3 + P5 = major triad (or M3 + m3)
 m3 + P5 = minor triad (or m3 + M3)
 m3 + dim5 = diminished triad (or m3 + m3)
 M3 + Aug5 = augmented triad (or M3 + M3)
HOW TO BUILD A TRIAD
If you know what the major triad is, then you can easily adjust the third and the fifth to create the
other chord qualities.
 From major, raise the fifth to create an Augmented Triad.
 From major, lower the third to create a Minor Triad.
From major, lower the third and the fifth to create a Diminished Triad, or
From MINOR, lower the fifth to create a Diminished Triad.
TRIAD STABILITY
A triad that is a combination of the strongest intervals is the most stable. The perfect fifth is by far the
strongest interval, and this accounts for the superior stability of the major and minor triads.
 Major Triad
Minor Triad
Diminished Triad
Augmented Triad
Strongest and most stable
Strong and quite stable
Weak and unstable
Weak and unstable
TRIAD NAMES
You can construct a triad on any of the scale degrees. The triad has the same function name as the
individual pitch. Both the pitch C and the C major triad are the tonic in the following figure.
TRIAD POSITION
Triad Position identifies the note of the chord that appears as the lowest-sounding pitch of the
harmony. Any of the three notes of the triad can appear as the lowest-sounding pitch.
ROOT POSITION – No matter what the arrangement of the third and fifth factors, the triad
is in root position if the root of the triad is the lowest-sounding pitch. All of the triads below are in
root position.
TRIAD POSITION
 Triad Inversion occurs when the root is NOT the lowest-sounding pitch.
 FIRST INVERSION – Occurs when the third of the triad is the lowest-sounding pitch,
regardless of the arrangement of pitches.
 SECOND INVERSION – Occurs when the fifth of the triad is the lowest-sounding pitch,
regardless of the arrangement of pitches.
TRIAD INVERSION SUMMARY
FOOD FOR THOUGHT: Can you
describe the difference between the
BASS and the ROOT?
HEARING TRIAD INVERSION
IDENTIFYING TRIADS IN MUSIC
The ability to recognize triads in music is critical to Score Analysis.
What triads do you see?
Keep in mind that triads may not always “line up” as they do in the Red Box.
They may be arpeggiated (as displayed in the blue circle).
They may also be staggered (as displayed in the green circle).
IDENTIFYING TRIADS IN MUSIC
Triads can also appear OUT OF ORDER in music as well. However, this is still an instance of an
A Major Triad in Root Position.
Introduction to Part Writing
 When studying harmony, we often will see a four-voiced texture called chorale style. Two
goals define this style:
INDEPENDENCE OF VOICES &
DEFINITION OF TONALITY
Voice leading controls the relationship between voices.
There are rules concerning doubling and chord voicing.
* What’s the point? The point is – you may see TRIADS presented in a chorale style format! Be ready!
Part-Writing Voices/Ranges
When constructing chords vertically for part writing, we use four voices.
The name and ranges of these voices are derived from the four standardized singing ranges
 SOPRANO
 ALTO
TENOR
BASS
 SOPRANOS/ALTOS are placed on the TREBLE CLEF of athe grand staff
TENORS/BASSES are placed on the BASS CLEF of the grand staff
We will discuss PART WRITING in much more detail later…