Inversions is the ‘classical’ name for what we often refer to as ‘slash’ chords, in which the lowest note is something other than the root.
In theory, an A major with a Root-3rd-5th of A-C#-E features the notes in ascending scale order with the root on the bottom. But if we flip this triad to have the 3rd on the bottom, then this gives a ‘first inversion’, or A/C# (C#-E-A).
A ‘second inversion’ flips things again, so we have the 5th on the bottom (E-A-C#). Expanding slightly on this concept, how about adding a dominant 7th, giving us a G in addition to the major triad? A ‘third inversion’ puts this 7th on the bottom, giving us G-C#-E-A.
We are also free to experiment with any other alternative bass notes or chord extensions on top. Composers as diverse as Bach and The Beatles certainly got some interesting results – check out Dear Prudence for a relatively recent example (which we reference in Example 4 below). Enjoy these chords and see you next time!
Example 1: A/C#
This chord could be correctly described as either an A first inversion (3rd on the bottom), or an A/C# in more contemporary ‘theory speak’. The open top E string would also fit in here, but I’ve chosen to omit it for clarity and highlight what’s happening in the low-end instead.
Example 2: A/E
This keeps the same basic shape and adds an E bass note, courtesy of the open sixth string. Listen to how this fundamentally changes the feel of the chord but without altering the overall harmony. This sounds great changing to a regular E major chord and gives a hint at how you might use inversions to make interesting chord changes.
I’ve chosen to call this A add9/E because, while it does have the 5th in the bass (second inversion), the add9 takes us a little outside the parameters of the original ‘inversions’ convention. Anyway, this lovely open-sounding chord could almost be in an open tuning or in an orchestral film score!
You can look at this chord as A7 with the 7th in the bass, A/G or as a third inversion. If you were to play it after a regular A major but before a D major over an F# bass, you would have a great example of how the bass notes can lead a chord progression such as The Beatles’ Dear Prudence.
Though this looks similar to Example 3 on the top four strings, there is no 3rd, so what was an add9 is now a sus2. The open fifth string would cloud the picture, so it’s muted to make room for the G at the 3rd fret of the sixth string. Inspired by A/G but with an extra twist.