Simply put, inverting a triad (chord) means to put a note other than the root of a chord as your bottomost note. You might know them as “slash chords.” Used well, inversions can give direction to your chord changes, and make them sound like they’ve got a real purpose for being there. Here’s how it works:
If you’re following a chord chart for a song, simply seeing a single-letter chord name means you play a major chord on that note. So seeing ‘A’ means to play an A major chord. Seeing ‘Am’ means to play the minor version of that chord. In so doing, you usually make sure that your bass player is playing an A. This is called playing the chord in root position. But as you know, there are three pitches in a triad, and more if the chord is more complex. You can get very interesting results by inverting the chord.
Instead of using A as your lowest sounding note, try one of the other pitches from that A major chord: the C# or the E. When you do this, a couple of things happen:
1. the bottom sounding interval is different. With an A major chord in root position, the bass is forming a major 3rd between itself and the next highest pitch in the chord (C#). By putting C# in the bass – called 1st inversion – it is forming a minor 3rd between itself and the next highest pitch (E). By using E as your bass note – called second inversion – it is forming a perfect 4th between itself and the next highest pitch. All of these possibilities are very noticeable if you give it a try.
2. With each inversion, the chord sounds a little less “stable.” Root position is the most stable, 1st inversion is a little less stable, and 2nd inversion is the least stable of all.
Now, an “unstable chord” is not at all to mean that it is somehow undesireable or unsuable. The best progressions, in my opinion, use a combination of root position chords and inverted chords. The normal way of notating an inverted chord is to use a “slash”, with the chord name first, then a slash, then the altered bass note. So the inversions described above would be A/C# and A/E.
But the question becomes when and how do we use them? Here’s some advice:
1. Try using a first inversion chord in between two chords whose roots are a 4th apart. For example, if you have this progression:
A A D E A
try this instead:
A A/C# D E A
The A/C# gives direction to your progression by giving direction to the bass line.
2. Use a first inversion chord to create a stepwise descending shape in your bass line. For example, instead of this:
A E F#m
try this instead:
A E/G# F#m
3. Use a second inversion chord to avoid using the same chord over and over. For example, instead of this:
A D A E A
try this instead:
A D A/E E A
The A/E gives you the A chord you need, but makes it sound different from the other A chords by providing a different note as the bass note.
Inversions, or slash chords, are a great way to add variety to your chord progressions, and can even add an air of sophistication to your changes.
-Gary Ewer from “The Essential Secrets of Songwriting” website.
