Goal
Understand how to identify and construct triads.
Triads
The first step beyond that of an interval is a triad. Triads are 3 note chords, hence “tri” in triad.
Stacked Thirds Formulas:
| Major Triad | Major 3 + Minor 3 |
| Minor Triad | Minor 3 + Major 3 |
| Diminished Triad | Minor 3 + Minor 3 |
| Augmented Triad | Major 3 + Major 3 |
There are other formulas that are possible. Instead of stacked thirds we can view triads as thirds + fifths. In doing it this way the formulas become:
3rd and a 5th Formulas:
| Major Triad | Major 3 and a Perfect 5 |
| Minor Triad | Minor 3 and a Perfect 5 |
| Diminished Triad | Minor 3 and a Diminished 5 |
| Augmented Triad | Major 3 and a Augmented 5 |
Now the quality of the chord (Augmented, Diminished, Major, Minor) should be a little more clear. When the 5th is perfect we use the third for the name. If the 5th is not perfect then we use the 5th for the name.
Root Note
The root note is the name of the chord. For example for G major the root note is G.
Triad Construction
We will use 2 ways to construct triads.
- Stacked thirds
- A 3rd and a 5th
For reference I typically use the 3rd and 5th method.
Stacked Thirds
Example 1:
Say we are asked to make a C Major triad. We start with a C since that is the name of the chord.
Now we look at the formula for the major triad which is a Major Third + Minor Third. So we go up a major third from C and add a note there:
We now have our first third, now we “stack” the next third on it by going up a minor 3rd from the E we just added. We get this:
The result is the C major triad!
Example 2:
Let's construct a G minor triad. We need the minor triad formula which is a minor third + major third.
First we place a G.
Now we go up a minor third and we have the following:
Now we go up a major third from the Bb:
Boom we now have a G minor triad!
We can follow the same process to create augmented and diminished triads.
A 3rd and a 5th
We can view each triad as a 3rd and a 5th. In this perspective we are not stacking, instead we are basing the relationship off the root note of the chord. This is why in the formulas I am careful not to use a + sign.
Example 3:
Let's say we are asked to make C Minor. To do so we use the minor triad formula which is
Minor triad = Minor 3rd + Perfect 5th
To start we put down the root note:
Then we go up a minor third from C and put that note down:
Then we go up a perfect 5th from C and put that note down:
Boom, a C minor triad.
Example 4:
Let's make a D diminished triad. We need the diminished formula: diminished triad = minor 3rd and a diminished 5th.
First we put down the root note:
Then we put down the the minor third above the root:
Next the diminished 5th above the root:
Boom! A D diminished triad!
Special Abbreviations and Chord Symbols
Chord symbols are a small easy way to write out the chords. For example, C Major is simply C. C minor is Cm, C diminished is C dim or C°, and C augmented is C aug or C+. Note that minor chords are sometimes denoted by a lowercase letter so C minor could be just c. This can be confusing when writing them down so I encourage you when writing the symbols to always use the small “m” as a way to be clear such as “Cm”. There are other chord symbols that will come up as we go further into the world of chords.
Practice
Chord Identification
Chord identification is just a matter of checking the intervals and seeing what formula they make!
Example:
Stacked Thirds Method:
Here we have a D as the root note. We see the F# is the third, a D to F# is a major third so that is the first interval. Next we check the F# to the A. This is a minor third, hence we have the formula major 3 + minor 3. This is the formula for a major chord! Therefore the chord is a D Major chord! Putting the chord symbol on top we have:
3rd and a 5th Method:
Doing the same problem with the 3rd and 5th method we have a D to F# which is a major 3rd and a D to A which is a perfect 5th, therefore the formula is major 3rd and a perfect 5th which again gives Major so this is a D Major chord.
Example 2:
A 3rd and a 5th method
Here we have G to Bb, which is a minor 3rd. Next we have a G to Db which is a diminished 5th. The formula is therefore minor 3rd + diminished 5th. So we must have a G dim chord or G°.
Stacked thirds method
Going from G to Bb we have a minor 3rd, going from Bb to Db we again have a minor 3rd. Therefore the formula is minor 3rd + minor 3rd again giving us a diminished chord.
Example 3:
A 3rd and a 5th method
Here we have an E to G# which is a major 3rd. Then we have an E to B# which is an augmented 5th. Therefore the formula is a major 3rd and an augmented 5th so the chord must be augmented. Hence it is an E+ or E aug chord.
Stacked 3rd’s method
E to G# is a major 3rd. G# to B# is a major 3rd. A major 3rd + major 3rd is augmented so it must be an augmented chord hence E+ or E aug.
Practice
You are going to need to get very good at this as we are going to attach this notion to scales and this greatly extends our ability to talk about harmony.
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