Dropping the 5th degree and counting a C♯Dom7

Question

I'm currently writing out (into a chord diagram book) all the different voicing/finger positions for the seventh chords.

Some voicings are difficult to play and I so my initial thought was "oh, the 5th note apparently is neutral so I can drop that and maybe the finger position will be a little easier to play".

The problem I'm having is being confident that the note I'm dropping is indeed the 5th degree, specifically when dealing with a chord whose notes have already been re-arranged into another voicing.

In short: I think my understanding (below) is correct and I'm just looking for confirmation from someone that there isn't some other crazy music theory concept I'm unfamiliar with that would mean I'm mistaken

So for example: A7 (dominant).

The root degrees are 1, 3, 5, ♭7 (A, C♯, E, G)

If I switch to 1st inversion I get the notes C♯, E, G, A (which are really the A7 degrees 3, 5, ♭7, 1)

If I try to play these notes in this order (C♯, E, G, A) on the guitar, I've found it to be a bit tricky for me still (that might just be my fingers not being as flexible as a long practicing guitarist, but whatever).

So if I decided I want to drop the 5th (a neutral note), which note should I drop?

I assume I'm still dropping the E note (which is the 5th as far as the root arrangement is concerned) because the new degrees (3, 5, ♭7, 1) don't actually make any sense as far as the major scale for C♯7 is concerned.

e.g. it's not like I can count the degrees like I would have done when originally calculating the notes for A7; So it wouldn't make sense to count: C♯ (1st), E (3rd), G (5th), A (♭7th) because those particular notes aren't the correct notes/order as far as C♯7 dominant chord is concerned (using the major scale). That would instead be: C♯ (1st), E♯ (3rd), G♯ (5th), B (♭7th)

So is my understanding correct?

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One additional question, how do you properly count the degrees for something like C♯7?

If I do it like so...

C♯, (W) D♯, (W) F, (H) F♯, (W) G♯, (W) A♯, (W) B♯, (H) C

...then this wouldn't be correct as we A.) have two F's in the arrangement and B.) don't end on the correct note for the octave.

But if I do it like so...

C♯, (W) D♯, (W) E♯, (H) F♯, (W) G♯, (W) A♯, (W) B♯, (H) C

...then here I've just assumed that you don't count F for the half-step and just go straight to F♯ as you know that E♯ is actually just F anyway.

But this doesn't appear to be correct either, as we've ended up with the octave not being the correct note.

Answer 1

The fifth of a chord can safely be dropped in any inversion. The fifth of a chord (perfect fifth) is always going to be the same note in reference to the root. Thus, root=A, means P5=E. It can't matter when there is a different voicing, as P5 will always be the same note in the same key. It has been said of a dominant chord on guitar that the 3 (C#) and b7 (G) are the most important, especially if the bass player uses the root A. Some of the shapes for A7 are tricky, in some inversions, so you could even make shapes that only use 3 strings - and they don't need to be adjacent to each other.

You ask about C#7. Be aware that the b7 in C# is B# flattened, making the dominant part actually a B note.

Answer 2

As an addition to Tim's answer, the two most common guitar voicings for dominant seventh chords with the fifth omitted and the root as the lowest note are (e.g., for C7, from low to high E string):

8 X 8 9 X X

and

X 3 2 3 X X

Since you mute three out of the six strings, these shapes can be shifted. They are very common in a blues and jazz context.

They allow other tensions to be added very easily. The first version allows you to add the 13th (on the b string) and the 9th (on the high e string):

8 X 8 9 10 10

Of course, you can also add the #5/b13 (9th fret b-string), or the b9 or #9 on the high e-string.

The other voicing lets you add the 9th (or the b9 / #9):

X 3 2 3 3 X (9)

X 3 2 3 2 X (b9)

X 3 2 3 4 X (#9)

These voicings finally also let you add the 5th (or an altered fifth) if you want it; you can find it on the high e-string. Some examples:

X 3 2 3 3 3 (C9 with 5th)

X 3 2 3 3 4 (C9/#5)

X 3 2 3 3 2 (C9/b5 or #11)

X 3 2 3 4 4 (C7/#5/#9 or C7/#9/b13)

Go wild finding all playable combinations ...