Fm7 Drop 2 1st inversion confusion

Question

I'm reading a guitar book that has started to describe drop voicing and inversions (both of which I'm already familiar with their concepts).

My concern is that I think my understanding of the concepts are slightly off (or not as nuanced as maybe the author's understanding).

He starts...

"Let's begin by learning the four voicings for a drop 2 Fm7 chord played on the top 4 strings (squares being the root)".

When discussing the Drop 2 voicing for Fm7 he provides a set of chord diagrams (one for each inversion: root, 1st, 2nd and 3rd).

But the second diagram, "Fm7 Drop 2 1st inversion", I noticed as not looking quite as I expected:

The Fm7 chord should be:

• ♮1: F
• ♭3: A♭/G♯
• ♮5: C
• ♭7: E♭/D♯

The 1st inversion of Fm7 would be:

• ♭3: A♭/G♯
• ♮5: C
• ♭7: E♭/D♯
• ♮1: F

Notice the ♭3 has been dropped into bass position
So the 1 is shifted up an octave, while the other notes follow the ♭3

This would then suggest the Drop 2 voicing of Fm7 1st inversion to be:

• ♭7: E♭/D♯
• ♭3: A♭/G♯
• ♮5: C
• ♮1: F

Notice the second highest note ♭7 has been dropped into bass position
While the other notes stay in their current ordering

But looking at the diagram the notes being played are:

• ♭3: A♭/G♯
• ♭7: E♭/D♯
• ♮1: F
• ♮5: C

Which (based on my earlier understanding of inversions and drop voicings) doesn't look to be correct, if he wanted to play a Drop 2 of the Fm7's 1st inversion?

Answer 1

Your confusion lies in the fact that you believe that the 1st inversion of the close voicing will result in a 1st inversion drop-2 voicing when the second note from the top is dropped one octave. This is not the case. As already pointed out by Tim, the lowest note in the voicing determines the inversion, regardless of the sequence of the other notes.

It turns out that the 3rd inversion of a close voicing of a four-part chord (e.g., Fm7) results in the 1st inversion of a drop-2 voicing:

3rd inversion close  =>    1st inversion drop-2

Eb - F - Ab - C      =>     Ab - Eb - F - C

The drop-2 voicing is in the 1st inversion because its lowest note is the (minor) third of the chord, i.e., the note Ab. The 1st inversion of the close voicing also has the third as the lowest note, but the sequence of the other three notes is different (Ab - C - Eb - F instead of Ab - Eb - F - C).

In a similar manner you can figure out the following relations:

root close     => 2nd inv. drop-2
1st inv. close => 3rd inv. drop-2
2nd inv. close => root drop-2

You have to look at the second note from the top of the close voicing, because this will become the bass note of the corresponding drop-2 voicing. And the latter determines which inversion you get.

Answer 2

An inversion is called with regard to the lowest note. Thus 1st inv. would have Ab as its lowest note. On piano, it's very easy to follow on with the rest of the notes going up sequentially, but, due to the tuning of the guitar, it's often not possible to keep the order. So, as long as the other three notes are present, their order is said not to be important, only that for the inversion, the correct note is at the bottom - Root =root=F. 1st inv. =b3 =Ab, 2nd inv. = 5 = C, and 4th inv. = b7 = Eb.

Drop 2 voicing for root is R,5,b7,b3, and the one in question, 1st inv. is b3,b7,R,5 - as Ab,Eb,F,C. So it looks like it's correct.