An introduction to Chord Inversions
This music lesson is an introduction to chord inversions. Click the video below for a short demonstration and tutorial on how chords can be inverted to change their sound or provide smooth connections to neighbouring chords.
Chord Inversions in under 4 minutes
Basic Chord Structure
Here is an outline of the points covered in the tutorial.
Chords are formed by combining notes. Different combinations of notes produce chords with different names. One of the notes (and any octaves of it) is considered to be the most important chord tone and is called the root of the chord. That note lends its name to the chord. In the chords, C major, C minor, C 7th or any chord named C something, all C notes (at any pitch) will be considered the roots of the chord.
Staying with C major as an example, apart from the root note, C, and any octaves of it, the other notes are E & G plus any octaves of those notes. Those other notes are called the 3rd & 5th of the chord respectively. That's because (ignoring octave differences) they are a 3rd & 5th interval above the root note, C. Another way is to seem them in relation to the C major scale, in which they correspond with the 3rd and 5th notes of the C major scale - the major scale of the root.
The notes of any chord can be arranged in any order and at any pitch with unlimited note doubling at any octave. Think of a large choir singing the chord, C major. Some singers will be singing a particular C note, others will be singing C notes that are octaves above or below that while others will be singing E & G notes at various octaves. It's still C major. In theory, it's every bit as much C major as someone playing C major on a harmonica with no more than three single notes - one each of C, E & G.
Most often, the chosen lowest note of any chord, will also be the root of the chord. So, in a C chord of any type, C will most often be chosen as the lowest, or bass, note of the chord. The chord is then said to be in root position. Chords in root position sound at their most balanced.
If we place any note other than the root in the bass, then the chord is said to be inverted. If the 3rd of the chord is in the bass, the chord is in first inversion. If the 5th of the chord is in the bass, the chord is in second inversion. If the chord has more than three differently named notes, then even more inversions are possible.
Note that, as with chords in root position, the notes above the bass note can be in any order.
When the 3rd is in the bass, the chord is in first inversion. It has a consonant (blending) sound like the root position chord but is somewhat unstable and 'light on its feet'. It has an interesting edge and restlessness to it. It wouldn't normally be a good chord to end a piece of music on where the desired effect is strong stable and final but it makes a great connecting chord.
With the 3rd in the bass, the 5th and root of any major chord will form intervals of a minor 6th (m6) and a minor 3rd (m3) with the bass (ignoring octave differences). Deriving from classical "Roman numeral" analysis, first inversion chords are also known as six-three chords, or "chords of the sixth" and written as, for example, I - V6 - vi. The 3 isn't written as it's assumed. (The Roman numerals refer to the scale degrees that the chords are built upon).
Note* Minor chords will also be 'six-three' when in first inversion but the interval quality will change. C minor for example, in 1st inversion has notes: Eb G & C. Those notes form intervals of major 6th (M6) and Major 3rd (M3) above the bass.
Don't confuse this with a chord label, such as C6. That's a chord type meaning C major plus another note that's a major 6th above the root. Although 6th chords may be historically related to 1st inversion "chords of the sixth", its name isn't specifying that it's to be be played in 1st inversion.
In chord labels, first inversion chords may be shown as slash chords, such as C/E or Gm/Bb, etc.
Second-inversion chords have their 5th in the bass. That makes them very unstable and even dissonant (clashing) to an extent.
With the 5th in the bass, the 3rd and root of a major chord will form intervals of a major 6th (M6) and a perfect 4th (P4), respectively, with the bass (again, ignoring octave differences). Second-inversion chords are also known as six-four chords, and written as, for example, I64 in analysis writing. In chord labeling, they can be shown as slash chords, such as C/G.
Note* As is the case with first inversion minor chords, minor chords in second inversion will still be 'six-four' chords, like major chords, but the major 6th (G-E) will become a minor 6th (G-Eb).
The video shows two examples. One is its simple use in arpeggios. Where it provides some pitch depth but doesn't last long enough to cause any problems of dissonance or instability.
The other example is a cadential six-four progression, often used in classical music of the 'Common Practice Period' (CPP), which lasted from around 1650 to 1900 and includes the biggest names in classical music (Bach, Haydn, Mozart, Beethoven, Schubert, Brahms, Tchaikovsky and many more) at final cadence points, (e,g., section endings).
The first chord in the example (C major) is also the tonic chord, meaning the 'key chord' - the all-important chord of resolution. However, by being arranged in 2nd inversion, it's not stable. It sounds dissonant, and this dissonance is exploited by placing it on a strong beat and letting it resolve indirectly via an intermediary (dominant) chord to the final strong and stable root position chord.
(Note - the intermediary chord in a cadential six-four progression is the root position major chord built on the 5th scale degree of the key, known as the dominant. In our example, in the key of C major, that chord is G major. Using the Roman numeral system, the progression can be written as I 64 - V - I)
The final part shows how chords that have more than three (differently named) notes can also be inverted, but they can sound similar to other chords in other inversions. The chord, A minor 7th, for example, has exactly the same notes as C6.
Am7 in root position > A C E G (with C, E & G in any order)
Am7 in 1st inversion > C E G A (with E, G & A in any order)
C6 > in root position > C E G A (with E, G & A in any order)
- Chord construction - chord formula list for building...
This chord construction article explains how notes are combined to produce chords. It also includes a chord formula list of all the basic chord types and more.