Here’s a music theory riddle: When is a triad not a perfect little stack of thirds built on top of a root? Answer: When its voicing is open, or when it’s inverted. Voicing, or spacing as it’s referred to in some classical circles, simply refers to the way a chord is arranged.
Taking a look at open and close voicing
Sometimes, the notes of a triad are spread out over two or more octaves, with the different parts rearranged so that, for example, the root may carry the highest‐sounding note, or the third, or the fifth can carry the lowest‐sounding note.
The notes are still the same (C, E, G, for example) — they’re just located an octave or even octaves above or below where you would expect them in a normal triad. When all the notes of a chord are in the same octave, the chord is considered to be in a close voicing.
Here’s a C major chord with close voicing.
The chord below, however, is also a C major chord, but with open voicing, meaning that the notes in the chord aren’t all located in the same octave.
Both chords have the same notes contained in the triad, but in the latter case the third has been raised a full octave from its close position. Both chords are still considered to be in the root position, because the root note, C, is still the lowest note of the triad.
Identifying inverted chords
If the lowest-sounding pitch of a chord is not the root, the chord is considered to be inverted. Here are the possible inversions of a triad:
First inversion: If the third of a chord is the lowest‐sounding note, the chord is in first inversion.
Second inversion: When the fifth of a chord is the lowest‐sounding note, the chord is in second inversion.
Third inversion: When the seventh of a chord is the lowest‐sounding note, that chord is in third inversion.
So how do you identify inverted chords? Simple: They aren’t arranged in stacks of thirds. To find out which chord it is, you have to rearrange the chord into thirds again. Only one way exists to rearrange a chord into thirds, so you don’t have to guess on the order of the notes. You may need a little patience, though.
Look at, for instance, these three inverted chords.
If you try moving the notes up or down octaves (in order to rearrange them so they’re all in stacks of thirds), they end up being an F sharp major triad, a G diminished seventh, and a D major triad.
From rearranging the chords, you can tell that the first example was an F sharp major in second inversion, because the fifth was the lowest‐sounding note in the chord. The second example was a G diminished seventh, also in second inversion, because the fifth of the chord was at the bottom of the stack. The third example was a D major triad in first inversion, because the third of the chord was the lowest‐sounding note.