Triad Inversions

Review: Triad Terms

1. The bottom note in a triad, when stacked in 3rds, is called the Root
2. The middle note in a triad, when stacked in 3rds, is called the 3rd:
3. The top note in a triad, when stacked in 3rds, is called the 5th

To review Triads go to Understanding Triads and Types of Triads.

Inversions

The lowest sounding note in a triad is called the bass. Triads are not always written or played with the root as the lowest note. Just like an interval can be inverted, a triad can be inverted by making the bass a note other than the root.

Root Position

Root Position is when the bass (lowest note) in a triad is the root. Notice that a root position triad in close position (all three notes within an octave) will be stacked 3rds.

1st Inversion

First Inversion is when the bass (lowest note) in a triad is the 3rd. We can make the above root position triad into a 1st inversion triad by moving the root up one octave. In other words, we invert it one time. Notice that a 1st inversion triad in close position will have a 4th as the top interval.

2nd Inversion

Second Inversion is when the bass (lowest note) in a triad is the 5th. We can make the above first inversion triad into a 2nd inversion triad by moving the bottom note up one octave. In other words, we invert it a 2nd time. Notice that a 2nd inversion triad in close position will have a 4th as the bottom interval.

In all three of the above examples, the chord remains an E minor triad. The only thing that changes is the inversion.

How to Identify the Inversion of a Triad

Example Triad

1. Stack the triad in thirds (line-line-line or space-space-space) by moving notes up or down an octave. This will help you to determine the root position triad. In this example, we can move the bottom note up an octave to get it stacked in 3rds. We can now see that the triad is a C major triad.
    
2. Look at the original triad to determine the bass of the triad. In the example, the bass is a G.
3. Use the bass to determine the inversion.
   • Bass = Root: Root Position
   • Bass = 3rd: 1st Inversion
   • Bass = 5th: 2nd Inversion
   In the example, the original bass was the 5th of the triad. Therefore, the triad is a C major triad in 2nd inversion.

How to Build an Inverted Triad

Example: Build a 1st inversion D major triad.

1. Build the root position triad.
     
2. Place the correct note in the bass. A first inversion triad will have the 3rd in the bass.
     
Notice that it is not necessary to place the triad in close position unless you wish to do so. All that matters is that the correct note is in the bass.

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