25: Inversions of Seventh Chords

 

Inverting sevenths works exactly the same way as inverting triads, only we have one more possible inversion since we have one more note in the chord.

As before, when the root of the seventh chord is in the bass, we’re in root position, regardless of what the other voices are doing.

As before, when the third of the seventh chord is in the bass, we’re in first inversion.

As before, when the fifth of the seventh chord is in the bass, we’re in second inversion.

Now, the pattern continues, and if the seventh of the seventh chord is in the bass, we’re in third inversion.

Many years ago, I learned a trick that has helped me a lot to know immediately where the root of a seventh chord is: if you’re lucky enough that there’s an obvious second in the way something is voiced (I’ll show you all this in all the inversions in just a little bit), then the top note of the second is the root of the seventh chord. If it isn’t obvious, spell it out and rearrange the notes in such a way that they’re more compact, and this will become much more clear.

This A dominant seventh is in root position:
A close-up of a music note AI-generated content may be incorrect.

I know this, yes, because I can read bass clef, so I can see the bottom note is an A, but the trick still works: If someone says the chord is spelled from bottom to top, A C# E G A (even if you can’t read, or you don’t have the score in front of you), then you can know that the root of the chord is A since the second in the chord is the G to the A, and the top note of the second is the root of the chord.

Here, this E dominant seventh is in first inversion, spelled G# B D E. You can tell this is the case since the second is found between a D and an E, and the upper note in the second is always the root:

A black and white image of a musical note AI-generated content may be incorrect.

Using the trick again, you can see that in this seventh chord, the root is G, since D-F-G-B has a second from F to G, and G is the upper note, and that since the D is the bass note, we’re in second inversion.

A close-up of a music note AI-generated content may be incorrect.

Finally, here in brand-new third inversion, we can see the second in Db-Eb-G-Bb and immediately conclude the root of this seventh chord is Eb, as the higher note in the second between Db and Eb:
A close-up of a music note AI-generated content may be incorrect.

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