Triad inversions, and I-IV-I-V-I

In this lesson we will learn about inversions of the triad inversion. Using the chord pattern “I-IV-I-V-I”, we can both start to appreciate the practical need for inversions, and in doing so, learn some basic chord cadences.

The Roman numerals refer to scale degrees of a given key. We will simply play the triad associated with those Roman numerals. In the key of C major, I-IV-I-V-I spells C, F, C, G, C. Let’s first practice each chord individually:

We will now play all three chords in prescribed order:

The movement from IV to I is referred to as a plagal cadence, and V to I, an authentic cadence. Both cadence types are highly common in western music, and a familiarity with these three chords achieves a basic step in music learning.

The cadences here certainly gratify our musical senses, thought this particular exercise could be improved. The physical jump between this chords is wide, and as a result, lacks a desired playability and aural smoothness.

By reordering – or inverting – the notes of the F and G chord, we can achieve a smoother and simpler progression. To begin, try playing the following example

The second chord is an F chord, with C inverted down. Bottom up, the chord is built with a 4th and 3rd, contained within a 6th. The proper name for this triad is a 6/4 chord, but more commonly referred to as a 2nd inversion triad.

The second to last chord is still G, our V chord. Here, B is inverted down an octave. Bottom up, the chord is built with a minor 3rd, and 4th, all contained within a 6th. The proper name for this triad is a 6 chord, but more commonly referred to as a 1st inversion triad.

In summary, 1st inversion triads have the 3rd on the bottom. 2nd inversion triads have the 5th on the bottom. When the 1st – or root – is on the bottom, we refer to that simply as root position. Lets now play C, F and G major in all 3 inversions

and our cadence pattern once again, with the inversions annotated:

Now, let’s experiment with the same pattern, starting with C major in 1st inversion. To keep the elegance of our last pattern, we will have to adjust what inversion we use for the IV and V chords:

and now with C in 2nd inversion:

Now, let’s try all three versions in the key of F major:

and all three versions in the key of G

The next lesson with take us deeper into the V-I motion, and triad inversions.